Is Westminster, CO Tap Water Safe to Drink?
Yes, Westminster tap water is safe to drink. Hardness is low at 66 PPM, and no contaminants exceed health guidelines. Most homes here don't need treatment.
Hardness Scale: Where Westminster Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Westminster Compares
Westminster's water is 52% softer than the national average of 138 PPM - ranking in the bottom 65% for hardness nationwide. Most homes here do not need a softener. Within Colorado, it ranks #21 of 23 cities (33% below the state average of 99 PPM). Among large cities (200k-500k), Westminster ranks #108 of 165 for hardness.
What Westminster's Water Means for Your Home
Hardness: 66 PPM - Low Concern
Westminster's water is moderately hard at 66 PPM. You'll see some spotting on glassware and a film on shower doors over time, but it's not the kind of hardness that demands a full softener. A salt-free conditioner is worth considering if you have a tankless water heater or high-end fixtures.
Contaminants & Safety
Disinfection byproducts are the notable finding here. Westminster's water has TTHMs at 32.8 ppb and HAA5 at 9.73 ppb — both within legal limits, but the EWG health guidelines are far stricter. These byproducts form when chlorine reacts with organic matter during treatment. A whole-house activated carbon filter reduces both chlorine and its byproducts. Want the full picture? Request your utility's annual Consumer Confidence Report.
What's in the Treatment Process
Westminster's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 32.8 ppb (41% of the legal limit, but 219x the EWG guideline) and HAA5 at 9.73 ppb (16% of the legal limit, but 97x the EWG guideline). These are within legal limits, but the EWG sets much tighter thresholds based on cancer-risk research. A whole-house activated carbon filter reduces both chlorine and byproducts.
Chromium-6 was detected at 0.178 ppb, which is 8.9x the EWG health guideline. There's no separate federal limit for chromium-6, only total chromium. A reverse osmosis system is the most effective removal method. All measurements are within federal legal limits. The EWG guidelines represent a more conservative, health-based standard.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 66 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 164 PPM | < 300 PPM | 500 PPM | ✓ OK |
| PFAS (total) | 0 ppt | — | No total limit | ✓ ND |
| ↳ PFOA | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| ↳ PFOS | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| Lead | 1.3 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ✓ Low |
| Chlorine / Chloramine | 0.6 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | Not reported | 5 mg/L | 10 mg/L | N/A |
Recommendations for Westminster Homes
How to Test Your Water in Westminster
City-wide data is a solid starting point, but your specific tap might differ based on plumbing age, distance from the treatment plant, or seasonal changes.
Free option: Request City of Westminster's annual Consumer Confidence Report for official city-level data.
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About Westminster's Water Supply
Water Utility: City of Westminster
Water Source: Standley Lake, Clear Creek (Surface Water)
Population Served: 202,078
Hardness: 66 PPM (3.9 grains per gallon)
Westminster's drinking water comes from surface sources — Standley Lake, Clear Creek. Surface water requires more extensive treatment than groundwater, including coagulation, filtration, and disinfection. This heavier chlorination is why disinfection byproducts tend to be higher in surface-supplied systems. On the upside, surface sources often deliver softer water than deep aquifers. The system serves 202,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Westminster's Consumer Confidence Report (CCR) or test your own tap.
ZIP Codes Covered by This Report
This water quality data applies to all areas served by City of Westminster in Westminster, CO, including ZIP codes:
80030, 80031, 80035, 80036
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Westminster to Other Colorado Cities
Frequently Asked Questions About Westminster Water
Is Westminster tap water safe to drink?
Where does Westminster's water come from?
Do I need a water softener in Westminster?
What is the hardness of Westminster water in grains per gallon?
What are disinfection byproducts in Westminster's water?
Is chromium-6 in Westminster's water?
Can I drink Westminster tap water straight from the faucet?
How does Westminster compare to the Colorado average?
Data sources: Lead and copper data from EPA Safe Drinking Water Act LCR reporting. Contaminant data from utility-reported testing results. PFAS data from EPA UCMR5 (2023–2025). Hardness from USGS and municipal reports. Data reflects system-level testing results and may not match your specific tap due to neighborhood plumbing, season, or recent utility changes. For your utility's latest results, request their Consumer Confidence Report (CCR). Our methodology. Last updated: 2026-02-24.