Formed when chlorine used to disinfect water reacts with natural organic matter. Includes chloroform, bromoform, and related compounds. The trade-off: disinfection prevents waterborne disease, but creates these byproducts.
Why it matters
Long-term exposure above the MCL of 80 µg/L (0.080 mg/L) is associated with increased cancer risk and possible reproductive effects. The MCL is based on a running annual average, not a single sample.
What to do
If your system is near or above the limit, an activated carbon filter (including pitcher filters like Brita) can reduce THMs. Running water for a minute before drinking also helps, as THMs are volatile and dissipate.
HAA5 (ppb)▸
21.7 µg/L
What is it?
Another group of disinfection byproducts formed when chlorine reacts with natural organic matter. HAA5 measures the five most common species.
Why it matters
Long-term exposure above the MCL of 60 µg/L (0.060 mg/L) is associated with increased cancer risk. Like THMs, the MCL is based on a running annual average.
What to do
Activated carbon filters can reduce HAA5. If your system consistently approaches the limit, a reverse osmosis filter provides more complete removal.
Fluoride (ppm)▸
0.74 mg/L
What is it?
Naturally occurring mineral, also added to many water systems to prevent tooth decay. The MCL (4 mg/L) is much higher than the typical added amount (0.7 mg/L).
Why it matters
At levels near the MCL, long-term exposure can cause skeletal fluorosis (bone pain and tenderness). The secondary standard of 2 mg/L triggers a required public notice about dental fluorosis risk in children.
What to do
Levels below 2 mg/L are within the range considered safe. If above 2 mg/L, children under 9 may be at risk for dental fluorosis — talk to your pediatric dentist.
Simazine (ppt)▸
0.000029 mg/L
No additional information available for this contaminant.
Atrazine (ppt)▸
0.0000091 mg/L
What is it?
One of the most widely used agricultural herbicides in the US. Enters groundwater and surface water from cropland runoff, especially in the Midwest corn belt.
Why it matters
The MCL of 0.003 mg/L protects against cardiovascular and reproductive effects. Atrazine is also an endocrine disruptor at very low levels.
What to do
Activated carbon filters can reduce atrazine. If you're in an agricultural area with detections near the MCL, a point-of-use filter is good protection.
Taste & appearance — not health-based
Aluminum (ppb)▸
0.027 mg/L
What is it?
Enters water from natural deposits and is also used in some water treatment processes (as a coagulant to remove particles).
Why it matters
This is an aesthetic standard (0.05–0.2 mg/L). Aluminum in drinking water may cause discoloration. The health effects of aluminum in water at typical levels are not well established.
What to do
No action needed at typical levels. If you notice discolored water, let the tap run for a minute.
Total Dissolved Solids (TDS) (ppm)▸
59 mg/L
What is it?
A measure of all dissolved minerals, salts, and metals in water. Higher TDS generally means "harder" or more mineral-rich water.
Why it matters
This is an aesthetic standard. TDS above 500 mg/L can affect taste and leave scale buildup on fixtures. Below 500 mg/L is generally considered good quality. Not a health concern.
What to do
No health action needed. If you have hard water or scale buildup, a water softener or reverse osmosis system can help.
Sulfate (ppm)▸
9.9 mg/L
What is it?
Naturally occurring mineral, common in groundwater near gypsum and shale formations.
Why it matters
This is an aesthetic standard. Sulfate above 250 mg/L can cause a bitter taste and laxative effects, especially for people not accustomed to it.
What to do
No long-term health action needed. Reverse osmosis or distillation can reduce sulfate if the taste bothers you.
Chloride (ppm)▸
6.1 mg/L
What is it?
Naturally occurring, also comes from road salt, water softener discharge, and industrial waste.
Why it matters
This is an aesthetic standard. Chloride above 250 mg/L gives water a salty taste. Not a health concern at these levels.
What to do
No health action needed. If the taste bothers you, a reverse osmosis filter reduces chloride.
Manganese (ppb)▸
0.0004 mg/L
What is it?
A naturally occurring mineral, often found alongside iron in groundwater.
Why it matters
This is an aesthetic standard, not health-based. Manganese above 0.05 mg/L can cause black or brown staining, and a bitter metallic taste. At very high levels (above 0.3 mg/L), there may be neurological concerns for infants.
What to do
A whole-house filter or water softener can reduce manganese. If you have an infant and manganese is above 0.3 mg/L, consider using bottled water for formula.
No US limit — WHO recommendation
Sodium (ppm)▸
3.5 mg/L
What is it?
Naturally present in most water sources. Also increases from road salt, water softeners, and natural mineral deposits.
Why it matters
There is no federal MCL for sodium. The WHO suggests a guideline of 200 mg/L for people on sodium-restricted diets. For most people, sodium in water is a small fraction of dietary intake.
What to do
If you're on a sodium-restricted diet and your water is above 20 mg/L, talk to your doctor. For most people, no action needed.
MRDL
Chlorine (ppm)▸
1.06 mg/L
What is it?
Added intentionally to kill bacteria and viruses. A chlorine residual in your tap water means the disinfection is still active through the distribution system — this is by design.
Why it matters
The MRDL of 4 mg/L is the maximum allowed. Typical levels are 0.5–2 mg/L. Chlorine at normal levels is not a health concern — the disease risk from untreated water is far greater.
What to do
If you don't like the taste, let water sit in an open pitcher for 30 minutes or use an activated carbon filter. Both remove chlorine taste and odor.
Source: CHARLOTTE WATER Consumer Confidence Report 2024 · Extracted by WaterScore · Confidence: raw
Model estimates
Private Well Risk
Do you have or use a private well? Estimated contamination risk for wells in this area based on local geology and land use.
Details ↓
3 sites within 10 mi
Nearby Superfund Sites
3 EPA Superfund sites within 10 miles. Proximity does not necessarily mean your water is affected.
Details ↓
Surface water
Water Sources
Charlotte draws from surface water — Lake Norman and Mt Island Lake/Cat River. Drought directly affects reservoir levels and river flow. ⚠️ This region is currently under severe drought conditions — reservoir and river levels may be reduced.