Is Hamilton City, CA Tap Water Safe to Drink?
Graded A+ with no contaminants above EPA limits. Here's everything we tested and how Hamilton City ranks. What to do next ↓
98.2/100
waterverge.com Hamilton City, CA — Water Quality Report
Hamilton City's drinking water received a grade of A+ (98.2 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,799 residents using groundwater.
Lead levels were measured at 1.8 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
No violations are on record for this water system.
What to know about Hamilton City's water
Hamilton City ranks #7 out of 694 cities in California for water quality, placing it one of the best in the state.
Hamilton City relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
Hexavalent chromium (chromium-6) was detected at 2.28 µg/L in UCMR 3 testing. While below California's 10 µg/L limit and with no federal MCL set, residents sensitive to this contaminant may consider reverse osmosis filtration.
As a small community water system, Hamilton City may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Hamilton City has a clean compliance record with no violations on file, reflecting strong operational practices.
Water quality score
See methodology →Is Hamilton City, CA water safe to drink?
Based on EPA testing data, Hamilton City's tap water is generally safe to drink. The water system earned a grade of A+ (98.2/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 1,799 residents using groundwater (wells).
Recent water quality updates for Hamilton City
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Hamilton City's water quality assessment. Grade: A+ (98.2/100).
Federal disaster declaration (FEMA DR-3592). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4683). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Hamilton City's water supply.
Well within EPA limits.
Flood & environmental risk
Santa Clara County has experienced 8 federally declared disasters since 1982. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Guadalupe R, Saratoga C A Saratoga, Coyote C Nr Edenvale, Coyote C Ab Hwy 237 A Milpitas, Arroyo Hondo Nr San Jose.
Where does Hamilton City's water come from?
Hamilton City's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,799 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Guadalupe R (river), Saratoga C A Saratoga (river), Coyote C Nr Edenvale (river), Coyote C Ab Hwy 237 A Milpitas (river), Arroyo Hondo Nr San Jose (river).
What Hamilton City residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Hamilton City's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violations & advisories
Flood & disaster history
Santa Clara County has experienced 8 federally declared disasters since 1982. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.8 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Hamilton City compares by contaminant
Explore where Hamilton City ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Hamilton City's water comes from
Hamilton City's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 1,799 people through 1 water system.
Water bodies near Hamilton City
Hamilton City is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Hamilton City
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CAL-WATER SERVICE CO.-HAMILTON CITY | CA1110002 | 1,799 | GW |
How Hamilton City compares
Full California rankings →Hamilton City's score of 98.2/100 is above the average of 57/100 among major California cities. It outscores 10 of 10 nearby cities.
Nearby cities
View California rankings →About Hamilton City, CA
Wikipedia →San Jose, officially the City of San José, is the most populous city in the San Francisco Bay Area and Northern California, and the 12th-most populous in the United States, with 997,368 residents. The city's metropolitan area is home to nearly two million people, while the broader combined statistical area has a population of over nine million. Located in the center of the Santa Clara Valley on the southern shore of San Francisco Bay, San Jose covers an area of 179.97 sq mi (466.1 km2) and is the seat of Santa Clara County.
Learn more about your water
Guides and resources related to Hamilton City's water quality findings.
Explore water quality across Glenn
Frequently asked questions
Is Hamilton City, CA tap water safe to drink?
Hamilton City's water quality earned a grade of A+ (98.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #7 out of 694 cities tested in California.
What contaminants are in Hamilton City's water?
Lead was measured at 1.8 ppb (90th percentile). No violations on record.
How is Hamilton City's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Hamilton City?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Hamilton City's water come from?
Hamilton City's water is sourced from Groundwater. The city has 1 water system serving approximately 1,799 residents.
Is Hamilton City's groundwater at risk of contamination?
Hamilton City uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. Current testing shows the groundwater meets EPA standards. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Hamilton City's water compare to other cities?
Hamilton City ranks #7 out of 694 cities in California (better than 99% of state cities) and #50 out of 15744 cities nationally (100th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Hamilton City's small water system affect quality?
Hamilton City's system serves approximately 1,799 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has maintained a clean compliance record.