B66/100
San Diego Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 6,291 residents · Texas
What's In San Diego's Tap Water?
31
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
9
Violations (last 5yr)
3
Unresolved
5
Health-Related
TIER 3Unresolved
Disinfection byproduct treatment technique failure
When: June 30, 2025Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 2Unresolved
Treatment technique violation
When: October 17, 2024Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 3Unresolved
Reporting violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 17, 2024Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 3Resolved
Disinfection byproduct treatment technique failure
When: April 15, 2024 – April 26, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: April 1, 2024 – June 30, 2024Enforcement: Formal — state order issued
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: February 1, 2024 – February 29, 2024Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: January 1, 2024 – March 31, 2024Enforcement: Formal — state order issued
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: January 1, 2024 – March 31, 2024Enforcement: Formal — state order issued
TIER 2Resolved
Exceeded the Maximum Contaminant Level (running average)
When: October 1, 2023 – December 31, 2023Enforcement: Formal — state order issued
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
SAN DIEGO MUD 1
Population Served
6,291
Water Source
Groundwater
System ID
TX0660003
Frequently Asked Questions About San Diego Water
Is San Diego tap water safe to drink?
San Diego, Texas tap water receives a grade of B (66/100), which is considered good. Out of 31 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 San Diego's water?
31 contaminants were tested in San Diego's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does San Diego have any water quality violations?
Yes, San Diego has 14 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, TT, RPT. 5 of these are health-based violations, which are the most serious category.
Do I need a water filter in San Diego?
San Diego 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 San Diego's tap water come from?
San Diego's drinking water is sourced from groundwater and supplied by SAN DIEGO MUD 1. The system serves approximately 6,291 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is San Diego'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. San Diego'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 San Diego's water compare to other cities in Texas?
San Diego's water quality score of 66/100 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 San Diego's water quality?
If you have concerns about San Diego'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 (SAN DIEGO MUD 1) 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.