Weld County, Colorado
38 ZIP codes · Avg score 61/100 · Grade C · Updated 2026-06-03
Within Weld County, 38 tracked ZIP codes reveal moderate water quality — national standards are generally met, with some documented exceptions.
How Weld County Compares
How Weld County Compares
Weld County scores 1 points above the Colorado state average (60/100) and 7 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Weld County, Colorado
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 11.2 (asthma 10.7%, diabetes 9.5%)
Estimated additional annual cost per homeowner: $847, driven primarily by flood
Infrastructure: 0.327% avg pipe failure probability, 16% of ZIPs at high risk
46.2% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↓ Improving trendEPA violation counts by year across Weld County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 8 violations. Past 5 years: 20 total (20 health-based). Health-based violations are declining versus the prior 2-year window.
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $847
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
142,235 housing units in Weld County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Weld County
Remediation costs are relatively manageable for most homeowners in Weld County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Weld County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Weld County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Central Weld Cnty Water District | 7,662 | 105 |
| 2 | City of Greeley | 132,310 | 56 |
| 3 | Frederick Town of | 17,173 | 50 |
| 4 | Platteville Town of | 2,900 | 44 |
| 5 | Firestone Town of | 27,798 | 41 |
63 total water systems serve Weld County.
All ZIP Codes in Weld County
38 ZIP codes tracked in Weld County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 80644 | Kersey | 70 | B | 1 | $387K |
| 2 | 80650 | Pierce | 70 | B | 1 | $311K |
| 3 | 80651 | Platteville | 70 | B | 1 | $438K |
| 4 | 80514 | Dacono | 69 | C | 2 (1 health) | $448K |
| 5 | 80534 | Johnstown | 69 | C | 6 (1 health) | $510K |
| 6 | 80603 | Brighton | 69 | C | 1 (1 health) | $449K |
| 7 | 80615 | Eaton | 69 | C | 8 (1 health) | $489K |
| 8 | 80620 | Evans | 69 | C | 2 | $315K |
| 9 | 80642 | Hudson | 68 | C | 12 (2 health) | $568K |
| 10 | 80520 | Firestone | 66 | C | 6 | $449K |
| 11 | 80623 | Gilcrest | 66 | C | 0 | $287K |
| 12 | 80646 | Lucerne | 66 | C | 1 | — |
| 13 | 80648 | Nunn | 66 | C | 0 | $394K |
| 14 | 80742 | New Raymer | 66 | C | 1 | $238K |
| 15 | 80516 | Erie | 65 | C | 1 | $684K |
| 16 | 80543 | Milliken | 65 | C | 4 | $404K |
| 17 | 80611 | Briggsdale | 65 | C | 2 | $419K |
| 18 | 80643 | Keenesburg | 65 | C | 2 | $455K |
| 19 | 80504 | Longmont | 64 | C | 3 | $557K |
| 20 | 80530 | Frederick | 64 | C | 7 (1 health) | $449K |
| 21 | 80546 | Severance | 64 | C | 2 | — |
| 22 | 80610 | Ault | 64 | C | 4 | $403K |
| 23 | 80632 | Greeley | 62 | C | 5 | — |
| 24 | 80633 | Greeley | 62 | C | 5 | — |
| 25 | 80638 | Greeley | 62 | C | 5 | — |
| 26 | 80639 | Greeley | 62 | C | 5 | — |
| 27 | 80621 | Fort Lupton | 61 | C | 31 (4 health) | $426K |
| 28 | 80631 | Greeley | 61 | C | 5 | $300K |
| 29 | 80634 | Greeley | 61 | C | 5 | $405K |
| 30 | 80550 | Windsor | 60 | C | 6 | $539K |
| 31 | 80551 | Windsor | 60 | C | 6 | — |
| 32 | 80622 | Galeton | 53 | D | 0 | — |
| 33 | 80624 | Gill | 53 | D | 0 | $482K |
| 34 | 80645 | La Salle | 45 | D | 0 | $404K |
| 35 | 80612 | Carr | 40 | D | 0 | $608K |
| 36 | 80729 | Grover | 40 | D | 0 | $254K |
| 37 | 80732 | Hereford | 40 | D | 0 | $114K |
| 38 | 80754 | Stoneham | 40 | D | 0 | $235K |
Recommended Buyer Guides for Weld County
While many sites publish identical guide lists across every county they cover, the selection here changes by location — driven by the EPA, NSF, FEMA, and CDC datasets that describe the actual conditions documented for this jurisdiction in the federal record.
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Weld County, Colorado
Overview
Weld County in Colorado covers 38 ZIP codes with an average Home Safety Score of C (61/100).
29 of 38 ZIP codes have recorded EPA violations. 11 health-based violations have been documented.
← Back to Colorado water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.