California property tax starts at 1.0 percent of assessed value by Proposition 13. Then local voter-approved bonds and special assessments add roughly 0.10 to 0.20 percent depending on the tax rate area. Then, in newer Simi Valley neighborhoods like Big Sky and parts of Sycamore Grove, a Mello-Roos Community Facilities District (CFD) assessment adds another $1,800 to $4,500 per year on top of that. The calculator on this page estimates all three layers for the major Simi Valley neighborhoods. As with all the tools on this site, results are estimates only -- confirm your actual tax bill with the Ventura County Assessor and your CFD administrator.
What this calculator does (and what it doesn't)
This tool estimates the annual and monthly property tax on a Simi Valley home. It uses the Prop 13 base of 1.0 percent, a default local-bond add-on of 0.15 percent (typical for Simi Valley tax rate areas), and a tract selector that adds the typical CFD assessment for neighborhoods that have one.
It does not look up your specific parcel or assessment. It does not know if a previous owner paid off a CFD early (some Wood Ranch lots have, most newer Big Sky lots have not). It does not account for supplemental tax bills triggered by reassessment after sale -- when you buy at a price higher than the prior assessed value, you will receive a supplemental tax bill covering the gap from your purchase date to the next regular tax year.
The binding source of truth is your annual Ventura County property tax bill plus your CFD administrator's annual statement (often Koppel & Gruber, NBS, or Willdan for Simi Valley CFDs).
The math behind the numbers
Step 1 -- Prop 13 base. California Proposition 13 (passed 1978) caps the property tax base rate at 1.0 percent of the assessed value, with the assessed value increasing no more than 2 percent per year while you own. When the home sells, the new assessed value resets to the purchase price. On an $885,000 purchase: $885,000 * 1.0% = $8,850.
Step 2 -- Local voter-approved debt and direct assessments. On top of the 1.0% Prop 13 base, local jurisdictions levy ad valorem debt service for voter-approved bonds (school districts, community college, water districts). In Simi Valley tax rate areas, the typical add-on is 0.10 to 0.20 percent. Use 0.15 percent as a planning midpoint: $885,000 * 0.15% = $1,328.
Step 3 -- Mello-Roos (CFD assessments). A Community Facilities District (CFD), enabled by the 1982 Mello-Roos Community Facilities Act, lets local agencies levy a special tax to fund infrastructure for new development -- streets, parks, schools, fire stations. It is a fixed annual amount per parcel (not a percentage of value), it shows up on your property tax bill, and it stays until the underlying bonds are paid off (typically 25-40 years from formation). Older Simi Valley tracts have no CFD. Big Sky's CFD averages $3,000/year per home. See the Mello-Roos lookup for tract-level detail.
Step 4 -- Monthly impound. Most lenders collect property tax monthly with the mortgage payment and pay the bill in two installments (Nov 1 / Feb 1 due dates). Monthly impound = total annual tax / 12. The lender holds a cushion of 2 months of taxes by RESPA rule.
Try the calculator
Pick the tract and enter your purchase price. The calculator estimates annual tax (base + local + CFD) and the corresponding monthly impound.
Estimate only. Wood Ranch CFD status varies lot-by-lot. Verify with Ventura County Assessor and your CFD administrator.
A worked example: $885,000 home in Big Sky
Big Sky is the highest-CFD neighborhood in Simi Valley. A buyer purchasing a Big Sky home at $885,000:
Prop 13 base: $885,000 * 1.0% = $8,850. Local bonds (0.15%): $1,328. Mello-Roos CFD: ~$3,000/year (varies by phase; some Big Sky homes are $2,500, some $4,500). Total annual: ~$13,178. Monthly impound: ~$1,098.
Compare to the same $885,000 home in Bridle Path (no CFD): Prop 13 base $8,850 + local bonds $1,328 = $10,178 annual, $848 monthly. The CFD adds $250/month to the impound -- meaningful for qualifying.
What buyers typically forget
- Supplemental tax bill -- when you buy at a higher price than the prior assessed value, you receive a one-time supplemental bill covering the gap from your purchase date to the next regular tax year. Plan on a separate $2,000-$5,000 bill 4-6 months after closing.
- Mello-Roos escalator -- many CFDs include an annual escalator of up to 2% per year. The $3,000 you pay today may be $3,750 in 10 years.
- CFDs are deductible only in part -- the IRS does not consider the entire CFD a deductible property tax. Talk to your CPA about how much of the annual CFD qualifies for the SALT deduction.
- CFD payoff option -- some CFDs allow early payoff. The payoff figure is typically $30,000 to $60,000 for a residential lot. Whether that math works depends on how long you plan to own.
- Direct assessments not in the CFD line -- vector control, mosquito abatement, lighting and landscape maintenance districts each show up as separate small lines ($25-$150 each).
How this maps to your impound and qualifying
Lenders qualify you on the full PITI -- principal, interest, taxes, insurance -- not just principal and interest. A $300/month CFD raises your qualifying PITI by $300, which at a 43% back-end DTI requires roughly $700/month more in gross income to qualify.
Two homes at the same price can have very different monthly payments and very different qualifying thresholds. A Wood Ranch home and a Big Sky home, both $885,000 with 20% down at 6.75%, will have nearly identical P&I -- but the Big Sky home will have ~$250 more in monthly impound from the CFD alone.
Always run the qualifying math at the post-CFD impound, not the pre-CFD impound. If you are torn between two tracts, the CFD difference can shift which house you actually qualify for at the same monthly budget.
Simi Valley-specific tax factors
SVUSD vs Ventura County debt service. Local bonds passed by Simi Valley Unified School District, Moorpark College District, Ventura County Community College and special districts (vector control, water) all add small per-parcel charges. The 0.15% planning figure used in the calculator is a midpoint -- some tax rate areas hit 0.18%.
Wood Ranch CFD status varies. Wood Ranch was developed across multiple phases starting in the late 1980s. The original CFD bonds are now mostly paid off, but a small number of phases or special improvement districts may still carry small assessments. Verify per parcel via the Ventura County Assessor.
Sycamore Grove split. The detached side of Sycamore Grove carries a CFD averaging $1,800-$2,200. The attached/townhome side may also carry one. Plus there is an HOA separate from the CFD. Sycamore Grove buyers need to read three documents -- the prelim title, the CC&Rs, and the CFD disclosure -- to know their total monthly carrying cost.
When to confirm with a professional
Ventura County Assessor (assessor.countyofventura.org) has parcel-level assessment lookup. Pull the prior year's tax bill PDF to see every line. Your CFD administrator (printed on the prior tax bill) can confirm current CFD amount, remaining bond term, and any payoff option. Your lender sets the actual impound amount and cushion. Your CPA determines what portion of property tax + CFD is SALT-deductible.
If you want the actual property tax history of a specific Simi Valley address before writing an offer, ask me -- I will pull the prior year's bill and walk through the line items with you.
What Prop 13 actually does and doesn't do
Proposition 13 (1978) is the foundation of California property tax. Understanding what it does -- and what it does not -- avoids common buyer confusion:
What Prop 13 does: caps the ad-valorem tax rate at 1.0% of assessed value; limits assessed value growth to 2% per year while you own; resets assessed value to purchase price at change of ownership; requires a 2/3 voter supermajority to pass new local special taxes.
What Prop 13 does NOT do: it does not cap voter-approved bond debt service (those 0.10-0.20% add-ons are on top of the 1.0%); it does not cap Mello-Roos CFD assessments (those are special taxes, not ad-valorem); it does not cap parcel taxes (flat-dollar voter-approved fees); it does not protect you from a supplemental tax bill in the year of purchase.
Prop 19 (2020) modifications: as of April 2021, parent-to-child transfers no longer automatically retain the parent's low assessed value for inherited primary residences unless the child uses it as a primary residence within one year, and even then the exclusion is capped at $1M of value increase. Buyers planning to inherit Simi Valley property should talk to an estate attorney before assuming the old Prop 58 rules apply.
Senior portability: Prop 19 also expanded the ability of homeowners 55+ to transfer their base-year value when buying a replacement home anywhere in California, up to three times in their lifetime. This is a major planning tool for downsizing Simi Valley sellers.
What the calculator does not include
- Parcel taxes -- flat-dollar voter-approved fees like Measure J school bonds in some Ventura County districts. Typically $50-$200/year per parcel.
- Direct assessments -- mosquito and vector control, lighting and landscape maintenance districts, stormwater fees. Each adds $25-$150/year.
- Supplemental tax bill -- one-time bill 4-6 months after closing covering the assessment increase from your purchase date to the next regular tax year. Plan on $2,000-$5,000 separately.
- Annual escalator on CFD -- many Mello-Roos CFDs include a 2%/year escalator. Today's $3,000 becomes $3,750 in ten years.
- Homeowner Exemption -- if the home is your primary residence, file a Homeowner Exemption with the Ventura County Assessor for a $7,000 reduction in assessed value (~$70/year savings). Free to file, easy to forget.
How property tax bills are issued and due in Ventura County
California secured property tax bills cover the fiscal year July 1 through June 30. The bill is split into two installments, both due in different windows:
First installment -- covers July 1 through December 31. Due November 1, delinquent after December 10. Late penalty: 10% of the unpaid amount.
Second installment -- covers January 1 through June 30. Due February 1, delinquent after April 10. Same 10% late penalty plus a $20 cost.
Most Simi Valley homeowners with a mortgage pay through the lender's impound account, which holds the funds and remits to the county on or near the due date. Homeowners without an impound (paid-off home, or lender-allowed impound waiver with 20%+ equity) handle the two payments themselves.
Supplemental bills -- separate from the regular secured bill. Issued by the Assessor when a change in ownership or new construction triggers a reassessment. The supplemental bill covers the increase in assessed value from the event date to the next regular fiscal year. Often arrives 4-6 months after closing. Lenders do not impound for supplemental bills -- you have to pay it directly and either reimburse yourself from your impound or fund it from cash. Plan for it.
Unsecured bills -- separate personal-property bills (boats, business equipment, etc.). Generally not relevant to residential real estate buyers but mentioned for completeness.
Three Simi Valley property-tax scenarios compared
Same $885,000 home, three different Simi Valley tracts, to make the impact concrete:
| Scenario | Prop 13 base | Local bonds (~0.15%) | Mello-Roos | Total annual | Monthly impound |
|---|---|---|---|---|---|
| Bridle Path (no CFD, no HOA) | $8,850 | $1,328 | $0 | $10,178 | $848 |
| Wood Ranch (mostly paid CFD + HOA $300) | $8,850 | $1,328 | ~$200 | ~$10,378 | $865 (+ HOA) |
| Big Sky (active CFD ~$3,000) | $8,850 | $1,328 | $3,000 | $13,178 | $1,098 |
Across the three tracts, total annual tax ranges by ~$3,000 -- about $250 per month in impound -- on the same headline price. Add HOA dues (Wood Ranch typical $300/month, Big Sky $200/month, Bridle Path $0) and the monthly carrying-cost spread widens further. Buyers comparing across tracts need to model true PITI + HOA + CFD, not just principal and interest.
Pro tip: when you tour a Big Sky home, ask the listing agent for the current property tax bill. Most listing agents have it; if they hesitate, that is a useful signal. The CFD line on the bill is the truth.
Six things to ask before writing an offer in a CFD tract
- What is the current annual CFD assessment on this specific parcel? (request the prior tax bill)
- What is the maximum annual CFD per the Rate and Method of Apportionment?
- What is the annual escalator? (commonly 0-2%/yr)
- When does the CFD end? (bond maturity date)
- Can the CFD be prepaid, and what is the current payoff figure?
- Has the CFD been refunded recently or are refunding bonds anticipated?
- Beyond the CFD, what other direct assessments appear on the prior tax bill?
- Has there been any pending tax appeal or assessment dispute on this parcel?
Most listing agents in Big Sky and Sycamore Grove can answer the first one. The administrator (printed on the tax bill) answers the rest. Build these into your inspection-period checklist alongside the structural and termite walk-throughs.
Property tax planning when buying mid-year
If you close in February, you have owned the home for about 5 months of the fiscal year and the seller paid the first installment in November. Standard escrow proration credits you for the days the seller covered that you will own. The escrow officer handles the math. But several months after closing, the supplemental tax bill arrives reassessing the home to your purchase price for the period from closing to the next fiscal-year roll. Plan to write that check separately -- it is not in your impound.
If you close in August (early in the fiscal year), the first installment is due in November and your impound may not have enough cash yet. Some lenders require you to bring extra to closing to seed the impound; others allow a deferred true-up. Confirm with your loan officer before assuming.
Frequently Asked Questions
What is Mello-Roos?
A Mello-Roos Community Facilities District (CFD) is a special tax authorized by the 1982 Mello-Roos Act that lets local agencies levy a fixed annual assessment to pay off bonds that funded infrastructure -- streets, parks, schools, fire stations -- for a new development. It appears on your property tax bill and stays until the bonds are paid off.
Which Simi Valley neighborhoods have Mello-Roos?
Big Sky carries an active CFD averaging $2,500-$4,500/year. Parts of Sycamore Grove carry $1,800-$2,200/year. Older tracts -- Wood Ranch (mostly paid off), Bridle Path, Strathearn, Tamarack, the Knolls, Texas Tract -- have no Mello-Roos. See the full lookup at /simi-valley-mello-roos-lookup-by-tract.
How do I find my exact Mello-Roos amount?
Pull the property's prior-year tax bill from the Ventura County Treasurer-Tax Collector or Assessor's parcel lookup. The CFD is itemized on the bill with the administrator's phone number. You can also request the seller's last tax bill during escrow.
Can Mello-Roos be paid off early?
Sometimes yes, depending on the CFD's bond covenants. Payoff amounts for a residential lot typically run $30,000-$60,000. Whether it makes financial sense depends on your hold horizon and discount rate.
Does Mello-Roos increase each year?
Most CFDs include an annual escalator of up to 2% per year. Check the CFD disclosure or call the CFD administrator to confirm the specific escalator for your tract.
Why is the calculator using 0.15% for local bonds?
That is a planning midpoint for Simi Valley tax rate areas. Actual local debt service ranges from 0.10% to 0.20% depending on the parcel's TRA (tax rate area). Your actual bill will specify each ad valorem add-on.
Is Mello-Roos tax-deductible?
Partially. The IRS treats the portion that pays interest on bonds as potentially deductible property tax (subject to the SALT cap), but the portion that pays principal is generally not. Talk to your CPA -- the breakdown is on your CFD administrator's annual statement.
What is a supplemental property tax bill?
When you buy at a price higher than the prior assessed value, California reassesses the property to your purchase price. You will receive a one-time supplemental bill covering the increase from your purchase date to the next regular tax year. Plan on $2,000-$5,000 a few months after closing.
