Is Hillsboro, OR Tap Water Safe to Drink?
Yes, Hillsboro tap water is safe to drink. Hardness is low at 30 PPM, and no contaminants exceed health guidelines. Most homes here don't need treatment.
Hardness Scale: Where Hillsboro Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Hillsboro Compares
Hillsboro's water is 78% softer than the national average of 138 PPM - ranking in the bottom 82% for hardness nationwide. Most homes here do not need a softener. Within Oregon, it ranks #8 of 48 cities (20% above the state average of 25 PPM). Among cities (50k-100k), Hillsboro ranks #226 of 258 for hardness.
What Hillsboro's Water Means for Your Home
Hardness: 30 PPM - Low Concern
Hillsboro's water is slightly hard at 30 PPM. Most households won't notice any issues at this level. Scale buildup is minimal, and a water softener would be overkill. Hillsboro is softer than 82% of US cities. If you're thinking about water treatment, contaminant filtration is where to focus your money, not softening.
Contaminants & Safety
Disinfection byproducts are the notable finding here. Hillsboro's water has TTHMs at 34.5 ppb and HAA5 at 23.2 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
Hillsboro's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 34.5 ppb (43% of the legal limit, but 230x the EWG guideline) and HAA5 at 23.2 ppb (39% of the legal limit, but 232x 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 0.145 ppb, which is 7.3x 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) | 30 PPM | < 60 PPM | No federal limit | ✓ OK |
| Total Dissolved Solids | 40 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 | 1.1 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 | 0.282 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Good news for Hillsboro residents. Your water quality is generally good. Most homes in this area do not need a water softener. If you have concerns about lead (especially in buildings constructed before 1986) or chlorine taste, a point-of-use filter is the most practical and cost-effective solution.
How to Test Your Water in Hillsboro
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 Hillsboro's annual Consumer Confidence Report for official city-level data.
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About Hillsboro's Water Supply
Water Utility: City of Hillsboro
Water Source: Joint Water Commission (Hagg Lake, Barney Reservoir) (Surface Water)
Population Served: 92,632
Hardness: 30 PPM (1.8 grains per gallon)
Hillsboro's drinking water comes from surface sources — Joint Water Commission (Hagg Lake, Barney Reservoir). 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 93,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Hillsboro'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 Hillsboro in Hillsboro, OR, including ZIP codes:
97113, 97123, 97124, 97129
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Compare Hillsboro to Other Oregon Cities
Frequently Asked Questions About Hillsboro Water
Is Hillsboro tap water safe to drink?
Where does Hillsboro's water come from?
Do I need a water softener in Hillsboro?
What are disinfection byproducts in Hillsboro's water?
Is chromium-6 in Hillsboro's water?
Can I drink Hillsboro tap water straight from the faucet?
What water filter is best for Hillsboro?
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.