Total Trihalomethanes (TTHM) in Maryland Drinking Water
Maryland has 7,992 public water systems. 3891 have recorded total trihalomethanes (tthm) violations.
Total Systems
7,992
With Violations
3,891
EPA MCL
0.08
Population Served
6.0M
Total Trihalomethanes (TTHM) in Maryland: Key Facts
Total Water Systems
7,992
Systems with Violations
3,891
Lead Violations
56
Copper Violations
305
EPA Standard
0.08 mg/L
Water Systems with Violations in Maryland
| System | Population | Violations |
|---|---|---|
| RECKLEY SPRING COMMUNITY WATER | 78 | 555 |
| EWELL WATERWORKS COOPERATIVE | 75 | 495 |
| GOLDEN KAY APARTMENTS | 148 | 490 |
| TYLERTON WATERWORK COOPERATIVE | 100 | 460 |
| HILL WATERWORKS COOPERATIVE | 100 | 459 |
| MIDTOWN WATERWORKS COOPERATIVE | 34 | 455 |
| RHODES POINT SOUTH WATERWORKS | 100 | 444 |
| CEDAR MOBILE HOME PARK | 300 | 348 |
Health Effects of Total Trihalomethanes (TTHM) Exposure
Cancer risk
Long-term exposure increases bladder cancer risk
Reproductive effects
Some evidence of adverse pregnancy outcomes
Liver/kidney stress
High chronic exposure may stress liver and kidneys
Long-term exposure: increased risk of cancer (bladder). Some evidence of reproductive effects.
Frequently Asked Questions
Is there total trihalomethanes (tthm) in Maryland water?
Maryland has 7,992 public water systems. 3891 have recorded total trihalomethanes (tthm) violations based on EPA SDWIS data. If you are on a private well, your water is not covered by these regulations and should be tested independently.
How can I check my Maryland water for total trihalomethanes (tthm)?
Search for your water system using the WaterCheck system lookup, or contact your utility and request a copy of your Consumer Confidence Report (CCR). The CCR is published annually and lists all detected contaminants, their levels, and the EPA MCLs. For private wells, contact a state-certified lab for independent testing.
What is the EPA limit for total trihalomethanes (tthm)?
The EPA Maximum Contaminant Level (MCL) for total trihalomethanes (tthm) is 0.08 mg/L. Systems that exceed MCLs are required to notify customers and take corrective action.
Total Trihalomethanes (TTHM) at a Glance
Source
Byproduct of drinking water chlorination; reaction of chlorine with organic matter
How to Filter Total Trihalomethanes (TTHM)
- +Activated carbon filters reduce TTHMs effectively
- +Reverse osmosis also removes TTHMs
- +Letting water sit uncovered may reduce some volatile TTHMs