When: September 1, 2022 – December 8, 2022Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: August 1, 2021 – August 31, 2021Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2021 – November 3, 2023Enforcement: Resolving — corrective action underway
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
Rio Vista, Texas tap water receives a grade of B (64/100), which is considered good. Out of 21 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 Rio Vista's water?
21 contaminants were tested in Rio Vista's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Rio Vista have any water quality violations?
Yes, Rio Vista has 32 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MON, MR. 1 of these are health-based violations, which are the most serious category.
Do I need a water filter in Rio Vista?
Rio Vista 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 Rio Vista's tap water come from?
Rio Vista's drinking water is sourced from groundwater and supplied by CITY OF RIO VISTA. The system serves approximately 1,040 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Rio Vista'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. Rio Vista'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 Rio Vista's water compare to other cities in Texas?
Rio Vista's water quality score of 64/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our Texas state page to see how all cities in the state compare.
What should I do if I'm concerned about Rio Vista's water quality?
If you have concerns about Rio Vista'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 RIO VISTA) 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.