Water Quality

Water Quality Report

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Every year, Gwinnett Water Resources publishes the annual Water Quality Report containing important information about the quality of your drinking water. Gwinnett County’s water is tested for various organic and inorganic substances in strict adherence with state and federal regulations. In 2024, there were no U.S. Environmental Protection Agency Safe Drinking Water Act violations to report.

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The Department of Water Resources is responsible for providing high-quality drinking water to Gwinnett County. Our water supply comes from Lake Lanier, providing a uniform raw water that is naturally low in suspended materials, bacteria, dissolved organics, and metals. This raw water is processed by one of our two water production facilities, the Shoal Creek and Lanier Filter plants, before entering our distribution system of underground piping and storage tanks. Water production treatment plant staff continuously monitors and analyzes water quality around the clock to ensure drinking water in Gwinnett County meets or exceeds all federal and state regulations for safety, based on the Safe Drinking Water Act and the Clean Water Act. Simply put, our water is safe to drink.

Our Environmental Lab rigorously tests both the raw water coming from Lake Lanier and the finished (treated) water from the plants to ensure it continuously meets all water quality and safety regulations. The lab also tests water in some portion of the distribution system nearly every day, visiting more than 800 sites in the county at least four times a year.

Water Quality at Home

The water produced in Gwinnett County is safe to drink directly from the tap and does not require boiling or filtering beforehand. Most issues with tap water originate in home plumbing systems. For example, black specks in the water are usually a sign of degrading internal plumbing. You can visit Resident Responsibility  for information about what your responsibilities are as a homeowner.

We have compiled resources to answer some of the most commonly asked questions regarding water quality or home water quality below.


If you are having a water emergency, please contact us.

Home Brewers Water Quality Report

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Parameter Defined Minimum
Concentration
Detected
Maximum
Concentration
Detected
Average
Concentration

pH (SU)

Acidity level

6.78

8.51 7.26
Total Alkalinity (as CaCO3)

A measurement of dissolved alkaline substances in water that can neutralize acid.
dkh = a unit of water hardness, derived from the German Karbonathärte

0.89 dkh
(16 mg/L)

1.45 dkh
(26 mg/L)

1.12 dkh
(20 mg/L)

Bicarbonate Alkalinity (as HCO3)

A measurement of bicarbonate substances in water that can neutralize acid.

19.5 mg/L

31.7 mg/L

24.4 mg/L

Total Hardness (grains per gallon)

A measurement of how much calcium and magnesium are in the water.

1.05 grains per gallon

1.87 grains per gallon

1.34 grains per gallon

Calcium

Calcium is an element that is essential to life; it gets into the water through contact with rocks and soil.

4.8 mg/L

9.6 mg/L

6.8 mg/L

Magnesium

Magnesium is an element that is essential to life; it gets into the water through contact with rocks and soil.

1.4 mg/L

1.9 mg/L

1.5 mg/L

Sodium

Sodium is an element that is essential to life; it gets into the water through contact with rocks and soil.

5.8 mg/L

6.0 mg/L

5.9 mg/L

Chloride

Chloride is an important naturally occurring element; it gets into the water through salt deposits that the water comes in contact with and through water treatment.

7.15 mg/L

9.55 mg/L

8.00 mg/L

Sulfate

Sulfate is a naturally occurring chemical that enters the water naturally as well as from human activities such as fertilization or industrial activities.

3.04 mg/L

4.82 mg/L

3.79 mg/L