Water Filtration and Water Treatment Companies in Washington, DC
A plain, alphabetical directory of 23 companies that install or service whole-house water filtration, water softeners, reverse osmosis and well-water treatment, or test water, for homes and businesses in Washington, DC. Every entry was checked on the company's own website. We do not rate or rank anyone.
- Water testing (14)
- Water softeners (13)
- Water heater/plumbing (13)
- Whole-house filtration (12)
- Reverse osmosis (12)
- Drinking water systems (8)
- UV disinfection (6)
- Commercial water treatment (5)
- Well water treatment (4)
- Iron and sulfur removal (3)
Local water facts
- DC Water states that the District's drinking water comes from the Potomac River. The U.S. Army Corps of Engineers' Washington Aqueduct draws it at Great Falls and Little Falls, treats it at the Dalecarlia and McMillan plants, and DC Water buys the treated water and distributes it.
Source: DC Water, From the Potomac to your Pipes https://www.dcwater.com/node/811 - DC Water says it operates more than 1,300 miles of underground pipes that carry water from the treatment plant to private service lines.
Source: DC Water, From the Potomac to your Pipes https://www.dcwater.com/node/811 - The Washington Aqueduct normally disinfects with chloramine. Each spring it switches temporarily to chlorine to clean the distribution system; in 2026 the switch ran from March 23 through May 4, and customers may notice a slight change in taste and smell.
Source: DC Water, Chlorine Switch https://www.dcwater.com/resources/waterquality/chlorine-switch - DC Water's Lead Free DC program launched in 2019 with a goal of removing all lead service lines in the District by 2030. Its June 2023 update estimated 41,157 lead service lines to replace and launched a lead map where residents can look up their address.
Source: DC Water, Lead Free DC Plan Update and New Lead Inventory Map https://dcwater.com/about-dc-water/media/news/dc-water-releases-lead-free-dc-plan-update-and-new-lead-inventory-map - DC Water offers free annual lead testing. Kits are delivered to homes so residents can collect their own samples, and the utility advises filtering water for drinking and cooking until all lead sources are removed.
Source: DC Water, Lead FAQs https://www.dcwater.com/LeadFAQs
All companies, A to Z
Acker & Sons Plumbing & Heating
A Kensington plumbing and heating company that installs and services water filtration and treatment systems for a range of brands, serving Montgomery County, Washington, DC and Virginia.
Bond Water Technologies, Inc.
A commercial and industrial water treatment firm (not residential) serving Maryland, Washington DC, Virginia and the Carolinas. It handles cooling tower and boiler water, wastewater, and lab and Legionella testing.
Brian B. Quick Plumbing
A Maryland plumbing company with Beltsville and Reisterstown offices that offers water treatment in Washington, DC and Baltimore. It installs whole-house filters on the main line and water softeners, and maintains reverse osmosis and cartridge systems.
Chemstar WATER
A commercial water treatment company serving Maryland and Washington, DC. Its work covers cooling tower and boiler treatment, Legionella prevention and water management plans, closed-loop systems and lab testing for buildings.
Cherry Blossom Plumbing
An Arlington plumbing company serving Northern Virginia and Washington, DC. It offers free water testing for hardness, chlorine and sediment, then sizes whole-home carbon or sediment filtration, softeners or reverse osmosis to the results.
ClearWave Water Solutions
A Virginia water treatment company with an Arlington office and a Washington, DC service page. It offers free water testing, softener installation, reverse osmosis drinking water systems, whole-house filtration, salt-free conditioners and UV disinfection.
Douglas & Son Services
A Montgomery County home services company that serves Maryland, Northern Virginia and the Washington, DC region. It installs water filtration systems and water softeners for homes and light commercial properties.
DS Home Inspection Services, LLC
A home inspection company that offers water quality testing (iron, lead, nitrate, nitrite, bacteria and turbidity), lead and copper testing for older homes, radon-in-water testing and well water testing, with Washington, DC in its service area.
F.H. Furr Plumbing, Heating, Air Conditioning & Electrical
A Northern Virginia home services company with a DC Metro water treatment page. It installs water softeners, reverse osmosis units, point-of-use filters and point-of-entry whole-house filters.
Hague Quality Water of Maryland
A family-owned Maryland water treatment dealer whose Washington, DC page covers both municipal and well water. It offers free water testing, softeners, reverse osmosis, whole-home filtration, well treatment including UV, and commercial systems.
JM Plumbing & Heating
A Northern Virginia plumbing company whose water page covers whole-house filtration and multi-stage reverse osmosis for kitchen sink or refrigerator drinking water, with service in DC, Maryland and Northern Virginia.
Len The Plumber Heating & Air
A plumbing and HVAC company with Silver Spring and Beltsville offices that has a Washington, DC service area. It installs whole-house filtration and softeners, and for well homes it tests water and installs filtration, softening, disinfection (including UV) and reverse osmosis.
Logan Mechanical
A Prince George's County mechanical and plumbing contractor serving DC, Maryland and Northern Virginia. It installs, replaces, repairs and maintains water softeners and also lists water filtration installation and service.
Mallick Plumbing & Heating, Inc.
A Montgomery County plumbing company that says it serves parts of Northwest Washington, DC. It installs and services softeners (including commercial softening), whole-house filtration, reverse osmosis and UV, and tests municipal and private well water.
Master Plumbing
A Gaithersburg plumbing company serving Maryland and DC. It installs Aquasana water filters, maintains and repairs existing filtration systems of various brands, and offers water treatment consultations.
National Water Service
A Maryland water treatment and plumbing company that says it serves all of Washington, DC. Its DC page covers compact softeners for condos and townhomes, catalytic carbon filtration for chloramine, reverse osmosis and free in-home water testing; it also handles well water and commercial systems.
NextDay Inspect
A home inspection firm that offers water testing as a separate environmental service in Northern Virginia, Maryland and Washington, DC.
Peak Environmental
An environmental testing company with Poolesville and Columbia offices that offers home water testing across central Maryland, Northern Virginia and Washington, DC.
Plumber In DC
A DC plumbing company that says it serves the whole District. Its services include installing water conditioning and filtration systems and reverse osmosis, along with general plumbing.
Pristine Water Treatment
A Stafford-based water treatment company that lists Washington, DC among its service areas. It offers free in-home and paid lab water testing, softeners, iron, sulfur and acid-neutralizer systems, reverse osmosis, whole-house carbon filtration and UV for wells, and repairs most makes.
Roto-Rooter Plumbing & Water Cleanup (Washington, DC)
The Washington, DC branch of the Roto-Rooter plumbing network. Its local page says it installs and services salt-based, salt-free and dual-tank water softeners and also links to whole-house filtration and a hard water test.
Sila Heating Cooling Plumbing
A heating, cooling and plumbing company serving DC, Maryland and Virginia. It installs whole-home filtration at the main line, point-of-use filters, reverse osmosis and water softeners after hardness and water-quality testing.
Water Testing Labs of Maryland, Inc.
A water testing laboratory serving Maryland, Delaware, Washington DC and Northern Virginia. It tests water for personal use, real estate transfers and community water supplies, and sells test kits such as a lead and copper kit.
Viper Home Services can match you with up to three local installers. The matching is FREE for homeowners.
Get matchedHow to choose a water treatment company
- Test first. A certified lab test (on a well) or your utility's annual water quality report plus a hardness test (on public water) tells you what needs treating.
- Match the treatment to the problem. Hardness needs a softener, chlorine taste needs carbon, and iron, sulfur, acidity and bacteria each need their own stage.
- Check the license. Ask for the company's state contractor or plumbing license number and confirm it with the state.
- Get it in writing. Ask for the equipment model, what is included in installation, the warranty and the yearly maintenance cost.