Is Mason, OH Tap Water Safe to Drink?
Mason tap water is legally compliant, but one contaminant exceeds health guidelines. Specifically: PFAS above EPA limits (PFOS: 5.15 ppt — limit is 4 ppt each). A point-of-use filter is recommended for drinking and cooking water. Mason also has very hard water at 280 PPM.
Hardness Scale: Where Mason Falls
0Slightly
60Moderate
120Hard
180Very Hard
250Extreme
400+
How Mason Compares
Mason's water is 103% harder than the national average of 138 PPM. It ranks #92 out of 1000 cities in our database (harder than 91% of US cities we track). Within Ohio, it ranks #9 of 34 cities (28% above the state average of 219 PPM). Among major US cities (500k+), Mason ranks #9 of 100 for hardness. At this hardness level, water heaters run an estimated 51% less efficiently due to scale insulation, and major water-using appliances typically last 4 years less than the national average lifespan.
What Mason's Water Means for Your Home
Hardness: 280 PPM - Treatment Recommended
Mason has some extremely hard water. At 280 PPM (16.4 grains per gallon), your tap is loaded with mineral content carried in from the watershed geology. Here's the thing: it's perfectly safe to drink. The minerals won't hurt you. But they will hurt your wallet. That adds up. Hard water at 280 PPM increases household costs through scale-coated water heaters that use more energy, extra soap and detergent, and appliances that wear out faster. Most Mason homeowners don't realize it until the plumber shows up. That's 28% harder than the Ohio average.
Contaminants & Safety
Forever chemicals (PFAS) are worth watching here. Mason has PFOS at 5.15 ppt, exceeding the EPA's 2024 limit of 4 ppt per compound. PFAS are synthetic compounds that accumulate in your body over time. A certified carbon filter or reverse osmosis system with NSF P473 certification is the most effective protection. See the regulatory timeline.
What's in the Treatment Process
Mason's surface water supply requires heavy chlorination to stay safe — but that creates a tradeoff. The treatment process generates disinfection byproducts: TTHMs at 38.1 ppb (48% of the legal limit, but 254x the EWG guideline) and HAA5 at 8.17 ppb (14% of the legal limit, but 82x 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 0.117 ppb, which is 5.9x 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.
How Hard Water Affects Your Home
At 280 PPM, untreated hard water has measurable effects on household costs and appliance life:
- Water heater inefficiency: Scale insulation forces the heater to work harder (DOE estimates up to 22% more energy for heavily scaled units)
- Soap and detergent: Hard water reduces lathering, requiring significantly more product
- Appliance replacement: Water heaters, dishwashers, and washing machines fail 2-4 years earlier due to scale buildup
- Plumbing maintenance: Scale buildup in pipes reduces flow and requires more frequent service
Note: Impact varies by household size, water usage, and local energy costs. A home water test provides the most accurate assessment for your specific situation.
| Contaminant | Detected | Health Guideline | Legal Limit | Status |
|---|---|---|---|---|
| Hardness (as CaCO₃) | 280 PPM | < 60 PPM | No federal limit | ⚠ Very Hard |
| Total Dissolved Solids | 430 PPM | < 300 PPM | 500 PPM | ⚠ Elevated |
| PFAS (total) | 14.2 ppt | — | No total limit | Detected |
| ↳ PFOA | 0 ppt | 0 ppt | 4 ppt (2024) | ✓ OK |
| ↳ PFOS | 5.15 ppt | 0 ppt | 4 ppt (2024) | ⚠ Exceeds |
| Lead | 2 ppb | 0 ppb (no safe level) | 15 ppb (10 ppb in 2027) | ✓ Low |
| Chlorine / Chloramine | 1.3 mg/L | Taste threshold ~1.0 | 4.0 mg/L | ✓ Normal |
| Nitrate | 0.758 mg/L | 5 mg/L | 10 mg/L | ✓ OK |
Recommendations for Mason Homes
Our Top Picks for Mason (280 PPM)
Hard water at 280 PPM causes scale buildup, increased energy use, and premature appliance failure. A softener protects your plumbing and appliances.
Recommended Filter for Mason
PFAS exceed EPA limits (PFOS: 5.15 ppt — limit: 4 ppt each). A certified filter reduces these contaminants effectively.
See all filter recommendations for MasonQuick Fix for Chlorine: Shower Filter
At 1.3 mg/L chlorine, many Mason residents notice dry skin, brittle hair, and that "pool smell" in the shower. A shower filter installs in 5 minutes, no tools needed.
How to Test Your Water in Mason
With PFAS at 14.2 ppt in Mason's supply, confirming your home's specific levels is especially important. PFAS vary by neighborhood and can concentrate differently depending on your position in the distribution system.
Free option: Request City of Mason Water's annual Consumer Confidence Report for official city-level data.
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About Mason's Water Supply
Water Utility: City of Mason Water
Water Source: Great Miami River aquifer (Surface Water)
Population Served: 750,200
Hardness: 280 PPM (16.4 grains per gallon)
Mason's drinking water comes from surface sources — Great Miami River aquifer. 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. Despite the treatment process, mineral hardness from the watershed carries through. The system serves 750,000 residents.
Water quality can vary by neighborhood and season. For your exact numbers, request City of Mason Water'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 Mason Water in Mason, OH, including ZIP codes:
45034, 45036, 45039, 45040, 45054, 45065, 45103, 45107, 45111, 45113, 45114, 45118, 45122, 45133, 45140, 45142, 45146, 45147, 45148, 45150, 45152, 45154, 45155, 45158, 45159, 45160, 45162, 45171, 45172, 45174, 45176, 45618, 45624, 45646, 45660, 45679, 45693, 45697
If your ZIP code is listed above, this report covers your water supply. Water quality may vary slightly by neighborhood.
Water Softener Sizing for Mason
At 280 PPM (16.4 GPG), here is how to size a softener for your Mason home. Multiply hardness in GPG (16.4) by daily water usage (roughly 50 gallons per person). A family of four uses about 200 gallons/day: 16.4 GPG × 200 gal = 3280 grains/day. Over a 7-day regeneration cycle, that is 22,960 grains - a 32,000-grain softener is the right fit for most Mason households.
Compare Mason to Other Ohio Cities
Frequently Asked Questions About Mason Water
Is Mason tap water safe to drink?
Where does Mason's water come from?
Do I need a water softener in Mason?
How do I remove PFAS from Mason tap water?
What water filter is best for Mason?
Is Mason water safe for babies and infants?
Does Mason water damage tankless water heaters?
Do I need both a softener AND a filter in Mason?
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.
What Mason Homeowners Actually Buy
Prioritized for contaminant reduction for homes with 280 PPM water and PFAS above EPA limits.
Affiliate disclosure: we may earn a commission. Selection based on Mason's water data.