A94/100
Mountain House Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 24,948 residents · California
What's In Mountain House's Tap Water?
54
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2010.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
CITY OF MOUNTAIN HOUSE
Population Served
24,948
Water Source
Surface Water
System ID
CA3910027
Frequently Asked Questions About Mountain House Water
Is Mountain House tap water safe to drink?
Mountain House, California tap water receives a grade of A (94/100), which is considered excellent. Out of 54 contaminants tested, none exceed EPA maximum contaminant levels (MCLs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Mountain House's water?
54 contaminants were tested in Mountain House's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Mountain House have any water quality violations?
Yes, Mountain House has 2 EPA violation(s) on record, with the most recent in 2010. Violation types include MR, MCL. 1 of these are health-based violations, which are the most serious category.
Do I need a water filter in Mountain House?
Mountain House water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. All contaminants are within health goals.
Where does Mountain House's tap water come from?
Mountain House's drinking water is sourced from surface water and supplied by CITY OF MOUNTAIN HOUSE. The system serves approximately 24,948 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Mountain House's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Mountain House's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Mountain House's water compare to other cities in California?
Mountain House's water quality score of 94/100 earns a grade of A, which is considered excellent. This places Mountain House among the better-performing water systems in California. Visit our California state page to see how all cities in the state compare.
What should I do if I'm concerned about Mountain House's water quality?
If you have concerns about Mountain House's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (CITY OF MOUNTAIN HOUSE) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.