Disinfection Byproducts (TTHM & HAA5) in Drinking Wa...
Contra Costa Water District, the cities of Antioch, Martinez and Pittsburg, and the Diablo Water District (Oakley) · Knightsen, CA · 43,357 people served
Data: EPA SDWIS, ECHO, 2013 Consumer Confidence Report
Disinfection Byproducts (TTHM & HAA5) Detected in Contra Costa Water District, the cities of Antioch, Martinez and Pittsburg, and the Diablo Water District (Oakley)
Disinfection Byproducts (TTHM & HAA5) was detected at 4439 ppb in the Contra Costa Water District, the cities of Antioch, Martinez and Pittsburg, and the Diablo Water District (Oakley) water system serving Knightsen, Oakley (CA), exceeding the EPA limit of 80 ppb (TTHM) / 60 ppb (HAA5).
This system serves approximately 43,357 people across 2 ZIP codes.
Data source: 2013 Consumer Confidence Report (CCR) and EPA SDWIS/ECHO.
Detected Levels
| Contaminant | Level Detected | EPA Limit | Status |
|---|---|---|---|
| Total trihalomethanes | 4439 μg/L | 80 μg/L | Exceeds Limit |
| Haloacetic acids | 169.7 μg/L | 60 μg/L | Exceeds Limit |
Health Effects of Disinfection Byproducts (TTHM & HAA5)
Disinfection byproducts (DBPs) form when chlorine or other disinfectants react with naturally occurring organic matter in water. The two regulated groups are Total Trihalomethanes (TTHMs) and Haloacetic Acids (HAA5). Long-term exposure to elevated DBP levels is associated with increased risk of bladder and colorectal cancer. Some studies also link DBPs to reproductive effects including miscarriage and low birth weight. DBP levels tend to be higher in systems using surface water and during warmer months.
Source: CDC — Disinfection Byproducts; EPA.
EPA Standard
The EPA maximum contaminant level (MCL) for disinfection byproducts is 80 ppb (TTHM) / 60 ppb (HAA5), governed by the Stage 2 Disinfectants and Disinfection Byproducts Rule. Water systems that exceed this limit must notify consumers and take corrective action.
What You Can Do
- Install a granular activated carbon (GAC) filter — the most practical DBP removal method
- Point-of-use carbon filters (pitcher, faucet-mount, under-sink) can reduce DBP levels
- Letting water sit in an open container or aerating it can reduce some volatile THMs
- Reverse osmosis systems also remove DBPs effectively
- Contact your utility if you notice a strong chlorine taste or smell — DBPs may be elevated
- Check your system's annual Consumer Confidence Report for TTHM and HAA5 levels
Recommended Water Filters
The most effective treatment for disinfection byproducts removal is Granular Activated Carbon.
| Filter Type | Effectiveness | NSF Standard | Notes |
|---|---|---|---|
| Granular Activated Carbon (GAC) | 80-95% | NSF 53 | Most practical solution; replace filters per manufacturer schedule |
| Reverse Osmosis (RO) | 90-99% | NSF 58 | Very effective but higher cost and water waste |
| Aeration / Air Stripping | 50-90% | N/A | Effective for volatile THMs; less effective for HAAs |
ZIP Codes Served by This System
Check water quality for your specific ZIP code:
Related Resources
- Contra Costa Water District, the cities of Antioch, Martinez and Pittsburg, and the Diablo Water District (Oakley) — Full Water System Profile
- EPA: Disinfection Byproducts (TTHM & HAA5)
Detected Levels
| Contaminant | Level Detected | EPA Limit | Status |
|---|---|---|---|
| Total trihalomethanes | 4439 μg/L | 80 μg/L | Exceeds Limit |
| Haloacetic acids | 169.7 μg/L | 60 μg/L | Exceeds Limit |
Recommended Water Filters
The most effective treatment for disinfection byproducts removal is Granular Activated Carbon.
| Filter Type | Effectiveness | NSF Standard | Notes |
|---|---|---|---|
| Granular Activated Carbon (GAC) | 80-95% | NSF 53 | Most practical solution; replace filters per manufacturer schedule |
| Reverse Osmosis (RO) | 90-99% | NSF 58 | Very effective but higher cost and water waste |
| Aeration / Air Stripping | 50-90% | N/A | Effective for volatile THMs; less effective for HAAs |