Diamond Bar Property Tax Rate
The typical property-tax rate in Diamond Bar is about 1.1711% of assessed value (about 1.1711%–1.2519% across Tax Rate Areas) — the 1% Proposition 13 base plus voter-approved debt. A typical Diamond Bar single-family home is assessed at about $597,000 for existing owners. Estimate your own bill below.
At about 1.1711%, Diamond Bar is about the same as the LA County median of 1.1874%. See how it ranks among LA County cities →
See what's behind the Diamond Bar rate: browse Diamond Bar's Tax Rate Areas and their itemized ad-valorem levies →
Typical Diamond Bar property tax
| Property type figures | Typical single-family assessed value | Typical annual tax (median rate) | Ad-valorem rate |
|---|---|---|---|
| Diamond Bar | $597,000 | $6,991 | 1.171–1.252% |
Figures are medians for existing owners from the LA County roll; see the data & methodology.
Property tax in Diamond Bar, in context
On the 2025 Assessor roll, Diamond Bar's taxable property was assessed at about $13.0 billion in total — up 3.8% from the prior year. Its residential roll of roughly 17,600 parcels is about 76% single-family homes and 24% condominiums. A typical single-family home is assessed at about $597,000 — an existing owner's Proposition 13 base-year value, not today's market price — for a typical annual tax near $6,991. The typical single-family home dates to around 1977 and spans about 2,050 sq ft, and about 38% of them still carry a Proposition 13 base set before 2000 (a median base year near 2004) — a big reason long-time owners are assessed well below current prices.
Diamond Bar spans several Tax Rate Areas, so the ad-valorem rate ranges from about 1.1711% to 1.2519% depending on which voter-approved school and municipal bonds apply to a given parcel, all on top of the 1% Proposition 13 base. That figure is ad-valorem only: Mello-Roos (CFD) special taxes and fixed direct assessments — where a parcel sits in a district that levies them — are billed separately and vary parcel by parcel. Newer, master-planned developments are the most likely to carry Mello-Roos, so check your own bill for line items beyond the base rate.
Diamond Bar property tax vs. nearby cities
How Diamond Bar's typical rate and bill compare with its closest Los Angeles County cities. A higher rate reflects more voter-approved bond debt in that area, not a higher assessment.
| City | Distance | Typical rate | Typical bill |
|---|---|---|---|
| Diamond Bar (this page) | — | 1.1711% | $6,991 |
| Walnut | 3 mi | 1.1711% | $7,366 |
| Pomona | 5 mi | 1.2519% | $4,019 |
| West Covina | 6 mi | 1.1437% | $4,906 |
| Covina | 7 mi | 1.1757% | $4,926 |
Nearest cities by Census place center; distance is straight-line. Typical bill is the median single-family figure for existing owners, ad-valorem only (excludes Mello-Roos and direct assessments).
Paying property tax in Diamond Bar
Due dates (LA County)
- 1st installment: due Nov 1, delinquent after Dec 10
- 2nd installment: due Feb 1, delinquent after Apr 10
A 10% penalty applies after each delinquency date. Pay or look up your Diamond Bar bill by parcel (AIN) at the LA County Treasurer & Tax Collector — links below.
Just bought in Diamond Bar?
A purchase reassesses the home to its price and triggers a one-time supplemental tax bill on the difference. Estimate it with the supplemental tax calculator →
Ways to lower your Diamond Bar bill
Most owner-occupants qualify for the $7,000 homeowners' exemption. You may also qualify for the senior or disabled-veteran property-tax exemptions — check your eligibility before the next installment.
Due dates, paying, and who to contact
Secured property-tax due dates
- 1st installment: due Nov 1 · delinquent after Dec 10
- 2nd installment: due Feb 1 · delinquent after Apr 10
Statewide schedule; a 10% penalty applies after each delinquency date.
Official LA County sources
- LA County Property Tax Portal ↗Look up and pay your bill (all three agencies in one place).
- Treasurer & Tax Collector ↗Payments, due dates, and installment details.
- Office of the Assessor ↗Assessed values, exemptions, and appeals.
- Auditor-Controller ↗Tax rates by Tax Rate Area and direct assessments.
Frequently Asked Questions
What is the property tax rate in Diamond Bar, CA?
In Diamond Bar the typical ad-valorem property-tax rate is about 1.1711% of assessed value (roughly 1.1711%–1.2519% depending on the Tax Rate Area) — the 1% Proposition 13 base plus voter-approved debt. Mello-Roos and fixed direct assessments, if any, are extra.
How much is property tax in Diamond Bar?
The typical Diamond Bar single-family home is assessed at about $597,000 (a Proposition 13 base-year value for existing owners), for a typical annual tax near $6,991. A new purchase is taxed on its price — use the calculator for your number.
Learn More
Educational estimate only, not an official bill. Rates are ad-valorem only (excluding Mello-Roos and fixed direct assessments) and shown as an area range, not your parcel's exact Tax Rate Area. Confirm with the LA County Assessor and Auditor-Controller.