Diamond Bar, CA Home Safety: Home Safety 75/100
1 ZIP code · 2 water systems · Updated
ZipCheckup grade for Diamond Bar: B.
This ZIP looks solid, with a few items worth a quick check.
Residents of Diamond Bar generally live with tap water that beats the CA safety average on key EPA compliance metrics.
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: $2,100 per household.
- CDC health risk index: 10.71.
Who Supplies Your Water in Diamond Bar
2 independent water providers serve Diamond Bar, CA - 2 systems appear in federal records.
- 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 lead level (90th percentile): 0.0000 mg/L (EPA action level: 0.015 mg/L)
- 0 of 1 ZIP code with known status exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
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). Water contamination can correlate with respiratory and chronic health conditions.
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. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Heavily weighted toward older construction, Diamond Bar's housing stock carries a median build year of 1971. That profile puts a majority of homes in the era when lead-soldered copper plumbing was standard practice.
Over half of homes in Diamond Bar were built before 1986, when lead solder was banned. 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
The household financial picture for Diamond Bar homeowners is proportionally favorable - addressing documented issues claims a small slice of equity, and the cost-to-value ratio puts this area well within the manageable tier.
Remediation costs in Diamond Bar are relatively low compared to home values. The $1,100–$3,400 estimated range is a small fraction of median property value. 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 there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Older stock in Diamond Bar represents 77% of the inventory, and citywide monitoring runs at or above the federal action level - making an in-home read a standard household-level step.
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 <strong>$2,100</strong> 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