Can Unmarried Couples Use Proposition 19 Together? Co-Ownership Tax Base Transfer Rules

Related: Prop 19 Hub Article | Prop 19 Age Requirements | Prop 19 Filing Process

Unmarried couples can use Proposition 19 when purchasing together, but each person's eligibility is evaluated separately by the county assessor. If only one person qualifies to transfer their tax base from a primary residence, you have two options: accept a split tax assessment where each ownership share is taxed differently, or use an advanced strategy where the qualifying partner takes 100% title with legal protections for the non-titled partner. The right approach depends on your potential tax savings, relationship dynamics, and willingness to invest in proper legal documentation.

Is This Article for You?

This guide is essential if:

• ✅ You and your partner are buying property together in LA County
• ✅ At least one of you is 55+, severely disabled, or a disaster victim
• ✅ At least one of you currently owns a primary residence with a low tax base
• ✅ You want to understand both simple and advanced Prop 19 strategies

This article won't help if:

• ❌ You're married or registered domestic partners (different rules apply)
• ❌ Neither of you currently owns a primary residence
• ❌ Your only property is a rental or investment property
• ❌ You're looking for commercial property strategies

Reading time: 18 minutes | Potential savings: $75,000-250,000 over 20 years

Key Takeaways:

• Each partner's eligibility is evaluated independently—you're not treated as a unit
• Only primary residences qualify (rentals and investment properties don't count)
• Split title approach is simpler but may leave tax savings on the table
• Full transfer strategy can save $3,500-8,000+ annually but requires legal documentation
• Proper legal protections (promissory note, deed of trust, co-investment agreement) are essential for advanced strategies
• File both BOE-19-B forms simultaneously within 60 days of closing for best results

Quick Navigation

Section	Key Insight
How It Works	Each person evaluated independently, not as a unit
Common Scenarios	Three typical unmarried couple situations explained
Strategic Options	Split title vs. full transfer comparison
Legal Protections	Required agreements for advanced strategies
Filing Requirements	What each person needs to submit
Local Impact	Why this matters more in high-cost LA County

How Prop 19 Works for Unmarried Co-Owners

When unmarried partners purchase property together using Prop 19, the LA County Assessor doesn't treat you as a single unit like married couples filing jointly. Instead, they evaluate each person's ownership interest independently based on three factors:

1. Whether each person owned and occupied a qualifying primary residence before
2. What each person's tax base was on their previous property
3. How much of the new property each person is buying

This creates what's called a split tax assessment—where part of the property retains a transferred low tax base, and part is assessed at current market value.

The Core Question Every Unmarried Couple Must Answer

Before filing for Prop 19, you need to determine: Do both of us qualify, or just one?

Both qualify if:

• You each currently own separate primary residences, OR
• You both own and live in the same primary residence together (both on title)

Only one qualifies if:

• One partner owns the current primary residence, the other lives there but isn't on title
• One partner's other property is a rental, investment property, or vacation home
• One partner doesn't currently own any property

This determination completely changes your strategy.

Decision Tree: Will Both Partners Qualify for Prop 19?

START HERE: Do you BOTH currently own and live in the same primary residence together?

• YES → Who is on the title of that residence?
  • Both of you → ✅ Both can potentially transfer a proportional tax base
  • Only one of you → ⚠️ Only the title holder can transfer their tax base
• NO (You each have separate properties) → Is each property your primary residence?
  • Both are primary residences → ✅ Both can potentially use Prop 19 separately
  • One primary, one rental → ⚠️ Only the primary residence owner qualifies
  • Both are rentals → ❌ Neither qualifies for Prop 19 portability

Critical Rule: Rental properties, investment properties, and vacation homes do NOT qualify for Prop 19 tax base transfer, regardless of how long you've owned them or what your tax base is. Only properties that served as your primary residence qualify.

Common Unmarried Couple Scenarios

The following are hypothetical examples created for educational purposes to illustrate how Proposition 19 works in different co-ownership situations. These scenarios are based on common patterns we see in Los Angeles County but do not represent specific clients. Always consult with a qualified real estate attorney and tax professional for advice specific to your situation.

Scenario 1: Both Partners Live Together in One Person's Home (Hypothetical Example)

Current Situation:

• Sarah owns a $1.2M home in Pasadena (tax base: $300,000 from 1995 purchase)
• Tom lives with Sarah but owns a rental condo in Glendale worth $400K (tax base: $150,000)
• They're buying a $900K home together in South Pasadena as Tenants in Common (50/50)

The Challenge: Tom's rental property doesn't qualify for Prop 19 because it's not his primary residence. Even though he's owned it for 20 years and has a low tax base, the law specifically excludes investment and rental properties.

Standard Approach - Split Title Assessment:

• Sarah CAN transfer her $300,000 tax base → her 50% share = $150,000 assessed value
• Tom CANNOT transfer (rental doesn't qualify) → his 50% share = $450,000 assessed at market value
• Combined new tax base: $600,000

Tax Comparison:

• Without Prop 19: $900,000 × 1.25% = $11,250/year
• With Prop 19 (split): $600,000 × 1.25% = $7,500/year
• Annual savings: $3,750

Advanced Strategy - Full Transfer with Legal Protections:

After consulting with a real estate attorney, Sarah and Tom could instead:

1. Title property 100% in Sarah's name
2. Sarah transfers full $300,000 tax base to the property
3. Tom's $450K contribution protected by:
   • Promissory note documenting his investment
   • Deed of trust (second position) securing his interest
   • Co-investment agreement defining 50/50 profit split on sale

Result:

• New tax base: $300,000 (Sarah's full transfer)
• Annual taxes: $3,750 (at 1.25% LA County rate)
• Annual savings vs. split title: $3,750 additional
• 20-year savings: $75,000+

The Trade-Off:

• Legal documents cost $3,500 (one-time)
• Tom temporarily not on title (but legally protected)
• Complexity: High, requires attorney involvement
• Payback period: 11 months

Tom's Protection: Despite not being on title, Tom has enforceable legal rights through the deed of trust and promissory note. If Sarah defaults, dies, or tries to sell without honoring their agreement, Tom has a recorded secured interest in the property that protects his $450,000 investment.

Scenario 2: Each Partner Owns Their Own Primary Residence (Hypothetical Example)

Current Situation:

• Maria owns her primary residence in Eagle Rock: $800K home (tax base: $250,000)
• David owns his primary residence in Highland Park: $600K condo (tax base: $200,000)
• They're buying a $1M home together in Altadena as Tenants in Common (60/40)

Prop 19 Result (Straightforward - Both Qualify):

• Maria CAN transfer her $250,000 base proportionally (60% ownership = $150,000 of the base)
• David CAN transfer his $200,000 base proportionally (40% ownership = $80,000 of the base)
• Combined new tax base: $230,000

Tax Comparison:

• Without Prop 19: $1,000,000 × 1.25% = $12,500/year
• With Prop 19: $230,000 × 1.25% = $2,875/year
• Annual savings: $9,625/year
• 20-year savings: $192,500+

Why This Works Beautifully: This is the ideal scenario for unmarried couples. Both partners have legitimate primary residences with established low tax bases, so both qualify independently. No complex legal structures needed—just straightforward Tenants in Common ownership with each person filing their own Prop 19 claim.

Important Note: When they sell their original properties, each person must file a separate BOE-19-B form showing their previous tax base and their proportional ownership in the new property.

Scenario 3: Buying "Up" to a More Expensive Home (Hypothetical Example)

Current Situation:

• James owns primary residence in Glendale: $700K (tax base: $220,000 from 2003)
• Lisa owns primary residence in Burbank: $650K (tax base: $180,000 from 2005)
• Buying together: $1.5M home in La Cañada as Tenants in Common (50/50)

The Prop 19 "Greater Value" Calculation:

When you buy a more expensive home, Prop 19 doesn't give you a free pass on the full value. Instead, you add the difference in market value to your old tax base.

James's Calculation:

• Original home market value: $700,000
• New home share (50%): $750,000
• Difference: $50,000
• New tax base: $220,000 + $50,000 = $270,000

Lisa's Calculation:

• Original home market value: $650,000
• New home share (50%): $750,000
• Difference: $100,000
• New tax base: $180,000 + $100,000 = $280,000

Combined new tax base: $550,000

Tax Comparison:

• Without Prop 19: $1,500,000 × 1.25% = $18,750/year
• With Prop 19: $550,000 × 1.25% = $6,875/year
• Annual savings: $11,875/year
• 20-year savings: $237,500+

Key Insight: Even when "trading up," Prop 19 provides massive benefits. James and Lisa are still saving nearly $12,000 per year compared to a full reassessment, despite buying a home worth $150,000 more than either of their original properties.

Scenario Comparison Summary

Scenario	Purchase Price	Tax Base Result	Annual Tax	Annual Savings	20-Year Savings
Scenario 1: One qualifies (split title)	$900K	$600K	$7,500	$3,750	$75,000+
Scenario 2: Both qualify (ideal)	$1M	$230K	$2,875	$9,625	$192,500+
Scenario 3: Both qualify (trading up)	$1.5M	$550K	$6,875	$11,875	$237,500+

All calculations use 1.25% effective LA County property tax rate. Your specific rate may vary by Tax Rate Area.

Strategic Choice: Split Title vs. Full Transfer

When only one partner qualifies for Prop 19, you face a critical strategic decision. Let's compare both approaches using a real-world example.

Comparison: Standard vs. Advanced Strategy

Factor	Split Title Approach	Full Transfer Strategy
Tax Base	Partial (mixed assessment)	Complete low base transfer
Legal Complexity	Low (standard TIC purchase)	High (requires attorney)
Risk to Non-Titled Partner	None (both on title)	Medium (if properly documented)
Upfront Legal Cost	$0-$500	$2,500-$5,000
Annual Tax Savings	Moderate	Maximum possible
Best For	New relationships, equal protection	Long-term couples, large tax differential

When the Advanced Strategy Makes Sense

You should consider the full transfer approach when:

• ✅ The tax savings are substantial ($3,500+ per year difference between approaches)
• ✅ You're in a long-term, committed relationship (5+ years together)
• ✅ The qualifying partner can secure mortgage independently (or you're paying cash)
• ✅ You plan to own the property long-term (10+ years to maximize cumulative benefit)
• ✅ Both partners understand and accept the legal complexity
• ✅ You're willing to invest in proper legal documentation

Stick with split title when:

• ❌ Relationship is relatively new (less than 2-3 years)
• ❌ Tax differential between approaches is small (under $2,000/year)
• ❌ Non-qualifying partner is contributing majority of funds and wants title security
• ❌ Either partner uncomfortable with the legal complexity
• ❌ Planning to sell within 5 years (insufficient time to recoup legal costs)

Quick Decision Checklist: Which Strategy Is Right for You?

Answer these 5 questions to determine your best path:

Question	Yes = Full Transfer	No = Split Title
Is your annual tax savings difference $3,500+?	Consider full transfer	Split title safer
Have you been together 5+ years?	Consider full transfer	Split title safer
Will you own the property 10+ years?	Consider full transfer	Split title safer
Is qualifying partner comfortable with legal docs?	Consider full transfer	Split title safer
Is non-qualifying partner's investment under 50%?	Consider full transfer	Split title safer

Scoring:

• 4-5 "Yes" answers: Full transfer strategy likely worth the complexity
• 2-3 "Yes" answers: Either strategy viable—depends on your priorities
• 0-1 "Yes" answers: Split title approach recommended for simplicity and safety

Legal Protections for the Advanced Strategy

If you choose the full transfer approach (property titled 100% to qualifying partner), these legal protections are absolutely non-negotiable. This is not an area for DIY documents or handshake agreements.

The stakes: Without proper documentation, the non-titled partner has NO legal claim to their investment—even if they contributed $200K-600K. Courts have consistently ruled that gifts made to partners during relationships cannot be reclaimed if the relationship ends.

Why "Trust" Isn't Enough

Real risks without legal documentation:

• Partner dies → Their heirs inherit 100%, you get nothing
• Partner files bankruptcy → You're an unsecured creditor, lose everything
• Relationship ends → No proof of your investment, no legal claim
• Partner sells without your consent → Completely legal if you're not on title
• Partner takes out home equity loan → You have no say, no protection

These scenarios happen regularly. Don't assume your relationship is immune.

Essential Legal Documents

1. Promissory Note

This document establishes that the non-titled partner's contribution is a loan to the titled partner.

What it includes:

• Exact amount of the loan (down payment, closing costs contributed)
• Interest rate (can be 0% for partners, or market rate)
• Repayment terms (typically "due on sale" of the property)
• Default provisions

Why it matters: Creates a legally enforceable debt. If the titled partner dies, sells, or tries to exclude the non-titled partner, this document proves the financial obligation.

Recording: Can be recorded as public record, though it's optional. Recording provides superior protection by making it part of the public record.

2. Deed of Trust (Second Position)

This document gives the non-titled partner a secured interest in the property, similar to how a mortgage lender has security.

What it includes:

• Reference to the promissory note being secured
• Legal description of the property
• Trustee designation (neutral third party)
• Foreclosure rights if note isn't honored

Position priority:

• First position: Primary mortgage lender
• Second position: Non-titled partner's deed of trust
• Third position: Any other creditors

Why it matters: This is the most powerful protection. If the titled partner files bankruptcy, gets sued, or dies, the deed of trust ensures the non-titled partner's interest is secured.

The deed of trust has priority over unsecured creditors. This means your investment is protected even in worst-case scenarios.

Recording: MUST be recorded with the county to be effective. This makes it public record and establishes priority over later creditors.

3. Co-Investment Agreement

This document defines the economic relationship between the partners regarding the property.

What it includes:

• Each partner's initial contribution (down payment, closing costs)
• How ongoing costs are split (mortgage, property tax, insurance, repairs)
• Profit/loss sharing formula upon sale
• Decision-making authority (who approves major repairs, refinancing, etc.)
• Buyout provisions if one partner wants out
• Right of first refusal if titled partner wants to sell

Scenarios it addresses:

• One partner wants to sell, the other doesn't
• Relationship ends (breakup procedures)
• One partner becomes disabled or dies
• Property needs major repairs—who pays?
• One partner stops contributing to expenses

Why it matters: Prevents disputes by establishing clear rules upfront. Courts will enforce this agreement if the relationship ends badly.

Recording: Typically NOT recorded (kept private), but must be signed and notarized for legal validity.

4. Estate Planning Updates

Both partners need to update their wills or trusts to address the property arrangement.

Titled partner's estate plan must:

• Acknowledge the non-titled partner's secured interest
• Direct executor to honor the promissory note and deed of trust
• Consider leaving property to non-titled partner (or giving buyout option)
• Ensure heirs understand they don't have 100% ownership rights

Non-titled partner's estate plan should:

• Direct how their secured interest should be handled if they die first
• Designate who inherits their promissory note and deed of trust
• Consider whether heirs should demand repayment or maintain the arrangement

Why it matters: Without proper estate planning, the titled partner's heirs might claim 100% ownership. This forces the non-titled partner into expensive litigation to enforce their rights.

Updating both estates ensures clarity and prevents family conflicts during already difficult times.

Composite Case Study: How Legal Protection Saved a $450K Investment

This composite case study is based on multiple transactions handled by estate planning attorneys in the Los Angeles area. It illustrates the importance of proper legal documentation when using advanced Prop 19 strategies. Details have been modified for educational purposes and client privacy.

The Situation (2019):

• Christine (South Pasadena): $1.3M home, $280K tax base, selling
• Mark (lived with Christine): Owned rental in Long Beach (didn't qualify for Prop 19)
• Together purchased: $1.1M home in San Marino
• Mark contributed: $450,000 cash toward purchase
• Christine contributed: $200,000 plus assumed full mortgage

Their Attorney's Strategy:

1. Titled property 100% to Christine
2. Created $450K promissory note (Mark to Christine, due on sale)
3. Recorded deed of trust securing Mark's interest (second position behind mortgage)
4. Co-investment agreement: 60% Christine, 40% Mark profit split on sale

Tax Result:

• Assessment: $280K (Christine's full Prop 19 transfer)
• Annual taxes: $3,500 (vs. $13,750 without Prop 19)
• Ongoing savings: $10,250/year

What Happened (2023): Christine unexpectedly died in a car accident. She had updated her will per the attorney's advice, but her adult children (from previous marriage) initially contested the arrangement.

How Mark Was Protected:

• Deed of trust was recorded, giving him secured creditor status
• Promissory note proved his $450K investment
• Co-investment agreement established his 40% profit share
• Estate attorney quickly resolved dispute—children couldn't override recorded security interest

Outcome: Mark and Christine's children sold the property for $1.6M. After mortgage payoff, Mark received his $450K principal plus 40% of the profit ($200K). Without proper documentation, he would have received nothing—Christine's children would have inherited 100%.

Legal fees paid in 2019: $4,200
Mark's investment protected: $650,000

This composite case study is based on patterns seen in multiple estate planning cases involving Prop 19 co-ownership structures. Always consult with a qualified estate planning attorney for your specific situation.

The "Add to Title Later" Trap

Many couples mistakenly think: "We'll put it in one name now for the tax benefit, then add the other person to title later when we're more comfortable."

This is a costly mistake.

Why You Can't Add Title Later Without Penalty

The Problem: Adding someone to title after purchase is a change in ownership under California law, which triggers a partial reassessment.

Example:

• Year 1: Property titled 100% to Sarah, Prop 19 tax base $300,000
• Year 5: Sarah adds Tom to title as 50% owner (wants to "make it official")
• Result: Tom's 50% share is immediately reassessed at current market value
• If property now worth $1.1M → Tom's half = $550,000 assessed
• New combined tax base: $150,000 (Sarah's half) + $550,000 (Tom's half) = $700,000

What They Lost:

• They thought they were keeping $300,000 tax base
• Actually ended up with $700,000 tax base
• Lost $400,000 in Prop 13 protection
• Lost $5,000/year in tax savings (permanently)

The Lesson: Whatever title structure you choose at purchase is essentially permanent if you want to keep the full Prop 19 benefit. You cannot easily "fix it later" without triggering reassessment.

Three Critical Questions Before You Buy

Whatever title structure you choose at purchase is essentially permanent if you want to keep the full Prop 19 benefit. You cannot easily "fix it later" without triggering reassessment.

Ask yourself these three questions before finalizing your purchase:

Question	Why It Matters	Red Flag Answer
"Are we both comfortable with this title structure for 10-20 years?"	Title changes trigger reassessment	"We'll figure it out later"
"If only one of us is on title, do we have ironclad legal protections?"	Unprotected partner risks losing entire investment	"We trust each other"
"Have we consulted both a real estate attorney AND a tax professional?"	Complex strategies need professional guidance	"We'll handle it ourselves"

Critical Rule: If you answer "no" or "unsure" to ANY of these questions, pause the transaction and get proper advice. The wrong title decision will cost you thousands annually for decades.

The cost of getting it wrong:

• Adding partner to title later = partial reassessment (lose $50K-400K in tax base protection)
• No legal protection = risk losing $200K-600K investment if relationship ends
• DIY legal docs = unenforceable in court, providing no protection

The cost of getting it right:

• Attorney consultation: $500-1,000
• Full legal documentation: $3,000-5,000
• Value protected: $75,000-250,000 in 20-year tax savings

Critical Filing Requirements for Unmarried Couples

When filing Prop 19 as an unmarried couple, the process is more complex than for married couples because each person files independently. For complete filing instructions and required forms, see our detailed guide

Each Qualifying Person Files Separately

Unlike married couples who can file jointly, unmarried partners must each submit their own BOE-19-B form (Claim for Transfer of Base Year Value to Replacement Primary Residence).

Each form requires:

✅ Proof of age or qualifying status

• Copy of driver's license or birth certificate (showing 55+)
• OR Form BOE-19-DC physician certification (if severely disabled)
• OR documentation of wildfire/disaster damage (if disaster victim)

✅ Proof previous property was primary residence

• Recent property tax bill showing Homeowners' Exemption
• Utility bills in your name at that address
• Voter registration at that address
• California driver's license with that address

✅ Documentation of sale/purchase

• Final closing statement from previous property sale
• Purchase agreement and closing docs from new property
• Deed showing your ownership percentage in new property

✅ Calculation worksheet

• Your original tax base (from old property tax bill)
• Market value of old property (sale price)
• Market value of new property (purchase price)
• Your ownership percentage in new property
• Calculated new tax base

Ownership Structure Documentation

The LA County Assessor needs to know exactly how you're splitting ownership to calculate each person's tax base correctly.

You must provide:

• Purchase agreement showing ownership percentages
• Grant deed specifying "as Tenants in Common" with percentages
• If using advanced strategy (one name only): Recorded deed showing sole ownership

Common mistake: Vague ownership language like "as joint tenants" without specifying percentages. For Prop 19 purposes with unmarried couples, Tenants in Common with stated percentages is clearest and best.

Timing Is Critical

File both claims simultaneously (within days of each other) to avoid:

• Confusion at the assessor's office
• Partial reassessment while waiting for second claim
• Processing delays that cost you money

Filing deadline: Within 3 years of purchasing the replacement property. However, earlier is better:

• File within 1 year = Benefit applies from purchase date (retroactive)
• File after 1 year = You pay higher taxes until claim processes
• File after 3 years = Too late, benefit denied

Best practice: File within 30-60 days of close of escrow. Don't wait.

What Happens After You File

LA County Assessor processing timeline:

1. Acknowledgment: 2-4 weeks (confirmation they received your claim)
2. Initial review: 4-8 weeks (verifying documentation)
3. Possible requests for additional info: 2-3 weeks
4. Final determination: 8-12 weeks from initial filing

Total time: Typically 3-5 months for complete processing.

During this time:

• You'll receive property tax bills at the FULL assessed value (new market value)
• Pay these bills to avoid penalties
• Once claim is approved, you'll receive a corrected assessment
• County will refund overpayment (with interest if significant delay)

Red flag: If you haven't heard anything after 90 days, call the LA County Assessor's office directly at (213) 974-3211 to check status.

Why This Matters in Los Angeles County

LA County's high property values make Prop 19 particularly valuable for unmarried couples—but also make the strategic choice between split title and full transfer more consequential.

The LA County Advantage (and Challenge)

Why LA County is different:

1. Higher property values = Bigger tax savings from Prop 19
2. Longer ownership periods = More residents with 1980s-1990s tax bases
3. Steeper appreciation = 6-8x gains vs. 3-4x in other CA counties
4. Higher effective tax rates = 1.20-1.30% vs. 1.0-1.1% elsewhere

What this means for unmarried couples: The difference between split title and full transfer strategies can mean $4,000-8,000 in annual tax savings—or $80,000-160,000 over 20 years.

LA County Market Reality

Current median home prices in key areas:

Neighborhood	Median Price	Tax Impact of Wrong Strategy
Pasadena	$1,300,000	$6,500/year × 20 years = $130,000
South Pasadena	$1,450,000	$7,250/year × 20 years = $145,000
San Marino	$2,800,000	$14,000/year × 20 years = $280,000
La Cañada Flintridge	$1,950,000	$9,750/year × 20 years = $195,000
Altadena	$950,000	$4,750/year × 20 years = $95,000

Calculations show potential savings difference between optimal strategy and suboptimal approach

Local Reality: Long-Time Homeowners

Many LA County homeowners have held properties since the 1980s-1990s, creating massive tax base gaps.

Common scenario I see:

• Long-time homeowner: Purchased 1988, tax base $180K, home now worth $1.4M
• Partner: Owns rental condo (doesn't qualify for Prop 19)
• If they use standard split title: Lose half the benefit forever
• If they use full transfer strategy: Preserve the entire 1988 tax base

The stakes are higher in LA because:

1. Properties have appreciated more (6-8x vs. 3-4x in other CA counties)
2. Effective tax rates are higher (1.2-1.3% vs. 1.0-1.1% elsewhere)
3. Long-term ownership is more common (strong community ties)

Property Tax Rate Note

LA County's effective property tax rate varies by Tax Rate Area (TRA) but typically ranges from 1.20% to 1.30% due to:

• Base 1% constitutional rate (Prop 13)
• Local school bonds
• Infrastructure bonds
• Special assessments

For calculations in this article, I've used 1.25% as a reasonable average. Your specific rate depends on your exact location. Check your property tax bill or contact the LA County Assessor for your precise rate.

The Tenants in Common vs. Joint Tenancy Question

Should you buy as Tenants in Common or Joint Tenancy when using Prop 19 as an unmarried couple?

For Prop 19 Purposes: Tenants in Common Is Better

Tenants in Common (TIC) advantages:

• ✅ Each person's ownership percentage clearly defined (can be 50/50, 60/40, 81/19, anything)
• ✅ Assessor can easily determine how to split the tax base between you
• ✅ Unequal ownership shares match unequal contributions (fair if one person puts in more)
• ✅ Estate planning is clearer for unmarried partners (each person's share goes to their heirs)
• ✅ More flexibility in structuring the arrangement

Joint Tenancy complications:

• ⚠️ Assumes equal 50/50 ownership even if you contributed differently
• ⚠️ Less flexibility in defining each person's transferred tax base
• ⚠️ Right of survivorship means property automatically goes to surviving partner (overrides your will)
• ⚠️ May not align with your estate planning if you have children from previous relationships

Example: Why TIC Works Better

Couple's contribution:

• Partner A: $500K down payment, has $200K Prop 19 tax base
• Partner B: $200K down payment, has $150K Prop 19 tax base (also qualifies)

As Tenants in Common (70/30):

• Partner A's base: $200K × 70% = $140K
• Partner B's base: $150K × 30% = $45K
• Total: $185K tax base (reflects actual contributions)

As Joint Tenants (forced 50/50):

• Partner A's base: $200K × 50% = $100K
• Partner B's base: $150K × 50% = $75K
• Total: $175K tax base (less favorable for Partner A who put in more)

Fairness issue: Partner A contributed 2.5x more but gets same ownership under Joint Tenancy. Tenants in Common allows ownership to match contributions while still both using Prop 19.

Estate Planning Consideration

With Tenants in Common:

• Each partner's share goes to whoever they designate in their will/trust
• Allows you to leave your share to children from previous marriage
• Partner doesn't automatically inherit (unless you specify that)

With Joint Tenancy:

• Surviving partner automatically gets 100% ownership
• Overrides your will (right of survivorship supersedes)
• Your children from previous relationship get nothing
• Can create family conflicts

For unmarried couples, especially those with children from previous relationships, Tenants in Common provides crucial estate planning flexibility while still allowing full Prop 19 benefits.

Note: Consult with an estate planning attorney. This is general guidance, not legal advice for your specific situation.

Common Mistakes Unmarried Couples Make

Having worked with numerous unmarried couples on Prop 19 strategies in LA County, I see the same mistakes repeatedly. Here's how to avoid them:

Quick Mistake Reference

Mistake	Why It's Problematic	The Fix
Assuming both qualify automatically	Each person evaluated independently	Verify EACH person owns primary residence
Thinking rental property qualifies	Only primary residences transfer tax base	Must have Homeowners' Exemption
Not disclosing ownership structure	Delays processing, causes confusion	Submit clear cover letter with percentages
Using handshake agreements	No legal protection for non-titled partner	Invest $3K-5K in proper legal documents
Filing at different times	Creates processing confusion	File both forms same day
Forgetting 105%/110% timing rule	Adds unnecessary tax base	Time purchase strategically

Mistake #1: Assuming If One Qualifies, Both Qualify

The misconception: "My partner qualifies for Prop 19, so we're good."

The reality: Each person's eligibility is completely independent. Just because your partner can transfer their tax base doesn't mean you automatically can.

Check yourself: Do YOU personally own a primary residence with an established tax base? If not, you don't qualify—regardless of your partner's qualification.

Mistake #2: Thinking a Rental Property Qualifies

The misconception: "I've owned this rental condo for 25 years and have a great tax base. I can transfer that, right?"

The reality: Absolutely not. Prop 19 ONLY allows transfer from a primary residence—the home you actually lived in. It doesn't matter how long you've owned the rental or how low your tax base is.

The test: Did you claim the Homeowners' Exemption on that property? If no, it doesn't qualify.

Mistake #3: Not Disclosing Ownership Structure Upfront

The mistake: Filing Prop 19 claims without clearly explaining to the assessor how ownership is split.

Why it causes problems:

• Assessor can't properly calculate each person's tax base
• Delays processing (months of back-and-forth)
• You pay higher taxes during the delay
• Possible partial denial requiring appeals

The fix: Include a cover letter with your Prop 19 claims stating:

• "This property purchased as Tenants in Common"
• "Partner A owns 60%, Partner B owns 40%"
• "Both partners filing separate claims (attached)"
• Grant deed clearly showing ownership percentages

Mistake #4: Using Handshake Agreements for Advanced Strategy

The mistake: Choosing the full transfer strategy (property titled to one person) without proper legal documentation.

Real example I saw:

• Couple bought $1.1M home, titled 100% to girlfriend (she had Prop 19 benefit)
• Boyfriend contributed $400K cash, girlfriend contributed $200K
• No legal documents—just "trust"
• 2 years later: Relationship ended badly
• Girlfriend claimed it was her house entirely
• Boyfriend had no deed of trust, no promissory note, no co-investment agreement
• He lost the entire $400K investment (couldn't prove it wasn't a gift)

The lesson: If you choose full transfer strategy, the legal protections aren't optional—they're absolutely critical. Budget $3,000-$5,000 for proper attorney-drafted documents.

Mistake #5: Not Coordinating Filing Timing

The mistake: One partner files immediately, the other waits months to file.

Why it causes problems:

• Assessor processes first claim, doesn't know second is coming
• Issues partial assessment based on incomplete information
• Second claim creates confusion, requires reassessment
• Possible penalties for "incorrect" initial processing

The fix: Coordinate with your partner to file both BOE-19-B forms on the same day. Mail them together or deliver in person together.

Mistake #6: Forgetting About the 105%/110% Timing Rule

When buying a more expensive home, timing affects your calculation.

The rule:

• Buy replacement BEFORE selling original → 100% threshold
• Buy replacement WITHIN 1 YEAR after selling → 105% threshold
• Buy replacement IN 2ND YEAR after selling → 110% threshold

What this means: If your old home sold for $800K:

• Year 1 purchase → New home can be up to $840K (105% × $800K) before additional tax base added
• Year 2 purchase → New home can be up to $880K (110% × $800K) before additional tax base added

The mistake: Not strategically timing the purchase to maximize the threshold benefit.

Example:

• Partner A selling $800K home, buying 50% of $850K home
• If buys immediately → New share worth $425K, exceeds 100% of old value ($400K)
• Adds $25K to tax base unnecessarily
• If waits 1 year → 105% threshold = $420K, new share $425K only slightly over
• Adds only $5K to tax base (saves $20K in assessed value)

For unmarried couples: This timing calculation applies to EACH person separately. You may need to coordinate who sells when to optimize both partners' thresholds.

Frequently Asked Questions

Q: Do we need to be in a domestic partnership to use Prop 19 together?

No. Prop 19 doesn't require any specific legal relationship between co-purchasers. Each person is evaluated on their individual eligibility—whether you're dating, engaged, registered domestic partners, or just co-investing friends. The assessor only cares whether each individual person qualifies under the age/disability/disaster criteria and whether their previous property was their primary residence.

Q: What if we have very unequal ownership percentages, like 81% / 19%?

That's completely fine and actually quite common when contributions are unequal. The assessor calculates each person's proportional tax base based on their exact ownership percentage. With an 81/19 split: the person owning 81% gets 81% of their transferred tax base applied to the property, and the 19% owner gets 19% of their transferred base (or market value assessment if they don't qualify). The math works the same regardless of the split ratio.

Q: Can one person pay the entire down payment but we still both use Prop 19?

Yes. Who pays what doesn't matter to the county assessor. If you're both on title as Tenants in Common and both qualify for Prop 19, you can both transfer your tax bases proportionally, regardless of who wrote the checks. However, document all contributions in a co-investment agreement to avoid disputes later.

Q: What happens if we break up after buying the property?

The Prop 19 tax base stays with the property, not the people. If you both sell, both lose the transferred tax bases (buyer gets reassessed). If one buys out the other, that's a change in ownership—the transferred portion gets reassessed, but the remaining partner keeps their Prop 19 benefit on their existing share.

Q: We're both over 55 but buying our first home together—can we use Prop 19?

No. Prop 19 requires that you're transferring a tax base from a previous primary residence you owned. The benefit is portability of an existing low base, not a discount on new purchases. If neither of you currently owns a primary residence with an established tax base, there's nothing to transfer. You'd start fresh with the property assessed at your full purchase price (this is normal for first-time buyers).

Q: Does it matter which one of us is older?

Only for meeting the age requirement. Each person must independently be 55+, severely disabled, or a disaster victim to use Prop 19 for their ownership share. If you're 58 and your partner is 52, only you can transfer your tax base initially. Your partner could use Prop 19 later once they turn 55 (within the 3-year filing window), which retroactively adjusts their portion. Learn more about age requirements

Q: Can we change from split title to full transfer strategy after purchase?

No—not without triggering reassessment. If you initially title the property as Tenants in Common (50/50) with split assessment, you cannot later remove one person from title to get full transfer benefits. Removing someone from title is a change in ownership that triggers reassessment of that portion. The title structure you choose at purchase is essentially locked in if you want to preserve the Prop 19 benefit.

Q: What if my partner and I each have rental properties—can we use those?

No. Rental properties, investment properties, and vacation homes do not qualify for Prop 19 tax base transfer, even if you've owned them for decades. The law specifically requires that the previous property was your primary residence where you actually lived and claimed the Homeowners' Exemption.

Q: How much do the legal documents typically cost for the advanced strategy?

Budget $2,500 to $5,000 for a qualified real estate attorney to draft proper promissory notes, deeds of trust, and co-investment agreements for the full transfer strategy. This is a one-time cost that typically pays for itself within 4-14 months given the annual tax savings of $3,500-$8,000. This is not an area to cut corners—improper documentation can result in losing hundreds of thousands of dollars.

Q: We're not romantic partners—just siblings investing together. Does this still apply?

Yes, everything in this article applies equally to non-romantic co-investment relationships: siblings, adult parent-child partnerships, friends, business partners, etc. Prop 19 doesn't distinguish based on relationship type. The same eligibility rules, strategic options, and legal protections apply. In fact, the legal documentation is arguably MORE important for non-romantic partnerships since there's less social/emotional pressure to "do right by each other" if things go wrong.

Ready to Calculate Your Potential Tax Savings?

Choosing the right ownership structure when using Prop 19 as an unmarried couple can mean the difference between saving $4,000 per year and saving $12,000 per year—that's $160,000+ over 20 years.

Explore more Prop 19 strategies

The strategy you choose depends on five key factors:

• Your potential tax savings (is advanced strategy worth $3,000-5,000 in legal fees?)
• Your relationship dynamics (comfort level with complex legal protections)
• Each partner's individual eligibility (one qualifies, or both?)
• Your ownership timeline (selling in 5 years vs. keeping 20+ years)
• Estate planning considerations (especially with children from prior relationships)

I work with unmarried couples throughout LA County to structure Prop 19 co-ownership arrangements that maximize tax savings while protecting both partners' investments. I also collaborate with experienced real estate attorneys who specialize in the legal protections required for advanced strategies.

I can help if you:

• Need to determine whether one or both partners qualify for Prop 19
• Want to calculate exact tax savings under split title vs. full transfer scenarios
• Are ready to explore advanced strategies with proper legal protections
• Need referrals to attorneys and tax professionals experienced with Prop 19

Here's what a consultation covers:

1. Eligibility assessment for both partners
2. Tax savings calculation comparing both strategies
3. Risk/benefit analysis for your specific situation
4. Attorney and tax professional referrals
5. Timeline and filing requirements overview

Contact Justin Borges:

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🌐 Schedule Your Consultation

Free 20-minute consultation to evaluate your options and calculate potential savings. No obligation—just clear guidance on whether Prop 19 makes sense for your situation and which strategy maximizes your benefit.

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About Justin Borges

Justin Borges is a Pasadena-based real estate expert specializing in helping Los Angeles families navigate housing transitions. With extensive transaction experience and deep knowledge of Proposition 19 benefits, Justin works closely with real estate attorneys and tax professionals to ensure clients maximize their property tax savings while protecting all parties' interests in complex co-ownership strategies.

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Legal Disclaimer: This article provides general information about Proposition 19 and co-ownership strategies. It is not legal, tax, or financial advice. Property tax regulations and co-ownership arrangements are complex, and individual situations vary significantly. The advanced ownership strategies discussed require professional legal documentation—do not attempt them without consulting a qualified real estate attorney and tax professional. Always seek personalized advice for your specific circumstances.

Market Disclaimer: Real estate market conditions, property values, and tax rates change frequently. Data and examples presented reflect information available at time of publication. For current market analysis specific to your properties and situation, contact Justin Borges directly.