Diamond Bar, CA Home Safety: Home Safety 75/100
1 ZIP code · 2 water systems · Updated
ZipCheckup grade for Diamond Bar: B.
This ZIP has a few items worth a quick check.
Diamond Bar, CA scores in the upper band of the ZipCheckup grade.
How Diamond Bar Compares
Data: EPA SDWIS
What You Should Know About Diamond Bar Water
- Homes built before 1986: 77% - older plumbing may contain lead solder.
- Estimated remediation: $500 per household.
- Health risk index (ZipCheckup composite of CDC data): 10.71.
Who Supplies Your Water in Diamond Bar
Federal records list 2 water systems tied to Diamond Bar, CA. Of those, 2 are the primary providers, meaning service conditions, rate structures, and compliance histories can differ depending on where a property sits.
- B
- B
Overview
We track home safety data for 1 ZIP code in Diamond Bar, California (population ~44,779), covering 2 community water systems serving approximately 157,041 people region-wide. The EPA snapshots used for this build directly map water systems to 1 of 1 ZIP codes.
The available EPA record reports 0 violations for 1 ZIP code with a reported violation count.
Home Safety Score
Average Home Safety Score for Diamond Bar: B (75/100)
Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| PFAS MCL Screen | UCMR 5 testing against the covered federal MCLs |
| Radon Risk | EPA radon zone classification |
| Annual AQI | EPA AirData county-year median with at least 90 observed days |
Water Sources
Diamond Bar water systems draw from: Surface water.
Lead & Copper
- Average of reported 90th-percentile lead results: reported as 0 mg/L (a reported 0 is not proof of no lead; check the source record for its reporting limit) (EPA action level: 0.015 mg/L)
- 0 of 1 ZIP code with known status exceed the EPA lead action level
Radon Risk
1 of 1 ZIP records with known zones is in EPA Radon Zone 2.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 91765 | B | Walnut Valley Water District | 100,941 |
All ZIP Codes in Diamond Bar
- 91765 [B]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.
Health Outcomes in Diamond Bar
Source: CDC PLACES (County-level estimates). County health indicators are shown for context only and are not linked to this area's water records.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Housing & Infrastructure in Diamond Bar
With 77% of homes built before 1986, lead solder in plumbing is a potential concern. Federal law banned lead solder in drinking-water plumbing in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
By Census estimates, roughly half or more of the homes in Diamond Bar were built before 1986; the median build year is 1971.
Over half of homes in Diamond Bar were built before 1986, when federal law began restricting lead solder in drinking-water plumbing. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Diamond Bar Homeowners
Here the gap between local home values and the estimated repair bill is wide, so the percentage shown below for Diamond Bar stays at or under the 1% mark.
Estimated remediation costs in Diamond Bar can be compared with local home values. The $300–$800 estimated range can be set against the median property value; actual costs vary by home. Home values are 19% above the California average.
Lead Exposure Risk for Children in Diamond Bar
Why children are most at risk: The CDC states that no safe blood lead level in children has been identified. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
If you have young children or are pregnant, consider testing your home's water - especially if your home was built before 1986.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Historical NFIP Claim Context in Diamond Bar
Historical NFIP data for Diamond Bar contains 7 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $6,806. Among ZIP codes with claim records, 0% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. The $500 remediation estimate shown here excludes flood insurance and is not derived from NFIP claim count.
Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.
Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.
Deep Dive Reports
Detailed analysis for Diamond Bar, CA