Water softeners and filtration in Washington, DC

What does DC Water publish about Washington water?

DC Water buys treated drinking water from the Washington Aqueduct, which draws it from the Potomac River.

What does 84 to 194 mg/L mean for a Washington home?

84 to 194 mg/L is about 4.9 to 11.3 grains per gallon. The low end, 84 mg/L, is 36 mg/L under the 120 mg/L top of the USGS moderately hard class; Washington's high end, 194 mg/L, is 14 mg/L over the 180 mg/L line where the USGS very hard class starts. (USGS hardness classes)

Which systems fit Washington water?

How does a Washington quote work?

1. Send a request from one of the 57 Washington ZIP codes listed below.
2. An assessment at your home, where your tap can be checked against DC Water's published 84 to 194 mg/L.
3. You get a written quote listing what is included.
4. Installation and service by that company.

Common questions

How hard is the water in Washington?

Total hardness reported by DC Water: Average 139 ppm (8 grains per gallon), range 84-194 ppm (Calendar year 2025).

Is Washington water hard or soft?

Moderately hard to very hard. The low end, 84 mg/L, is 36 mg/L under the 120 mg/L top of the USGS moderately hard class; Washington's high end, 194 mg/L, is 14 mg/L over the 180 mg/L line where the USGS very hard class starts.

How many grains per gallon is Washington water?

In grains per gallon, as published: 8 grains per gallon (DC Water, total hardness, Calendar year 2025).

Where does Washington tap water come from?

DC water comes from the Potomac River, treated by the Washington Aqueduct and bought by DC Water. Source: DC Water 2026 Drinking Water Quality Report.

Does Washington water change over time?

For a short time each spring, the Aqueduct switches from chloramine to chlorine only. Source: DC Water 2026 Drinking Water Quality Report.

Is Washington water treated with chlorine or chloramine?

For most of the year, the Washington Aqueduct uses chloramine to keep DC water disinfected. Source: DC Water 2026 Drinking Water Quality Report. That matters when choosing a filter for a Washington home: catalytic carbon is the activated-carbon type designed to adsorb chloramine (NDSU Extension, Filtration: Sediment, Activated Carbon, and Mixed Media). A softener leaves DC Water's disinfectant in the water.

Do I need a water softener in Washington?

DC Water publishes 84 to 194 mg/L for Washington, which reads as moderately hard to very hard. A test at your house shows whether your tap matches it.

Is the water the same in every Washington home?

DC Water publishes one figure for its whole system (Calendar year 2025).

How much does a water softener cost in Washington?

We publish no prices for Washington. The installing company gives a written quote after an assessment at your home.

Who installs the system?

We have not named a local installing company for Washington yet. We will tell you the company's name and ask you before your request is shared with anyone.

Is DC Water Systems part of the city or the water utility?

No. DC Water Systems is not affiliated with DC Water; it copies and links the published figures.

Is booking an assessment a purchase?

No, and a request commits you to nothing.

Which ZIP codes does this page cover?

20001, 20002, 20003, 20004, 20005, 20006, 20007, 20008, 20009, 20010, 20011, 20012, 20015, 20016, 20017, 20018, 20019, 20020, 20024, 20032, 20036, 20037, 20045, 20052, 20057, 20059, 20064, 20204, 20220, 20230, 20240, 20245, 20250, 20260, 20317, 20319, 20373, 20388, 20390, 20408, 20415, 20418, 20422, 20427, 20431, 20510, 20515, 20520, 20530, 20535, 20540, 20542, 20551, 20560, 20565, 20566, 20591

Compare published hardness in other cities on hard water by city.

Machine-readable facts: water.json. Summary for AI assistants: llms.txt.