National Water Service
Company Overview
With over 45 years of experience, National Water Service has been installing and servicing complex water systems in residences, cafes, lodgings, hospitals, malls, and more across the DC, Bmore, and Frederick.
Our team partners with designers, contractors, and construction professionals to create bespoke solutions for water purification in both residential and business settings, including a complete selection of submersible pumps, pressure boosters, and more.
Whether you rely on public water or a well system, the quality of water can differ significantly from one street to another, and we are pleased to offer a complimentary analysis of your water and/or current water treatment system.
Our installers are all professionally trained in water purification, purification, and are recognized as certified well water specialists!
National Water Service sets the standard for residential water purification, water quality solutions, and provides a full line of well pumps, boosters, and more.
When it comes to domestic areas, one crucial factor for homeowners to consider is water quality. It’s essential to understand that whether you are on city water or a private well, water quality can vary significantly from one neighborhood to another. National Water Service is glad to conduct a basic analysis at no cost. If more extensive testing is required, we offer testing services as well.
National Water Service has been installing and servicing sophisticated water systems in restaurants, hotels, hospitals, malls, and various other locations throughout the District of Columbia Metro area for over 30 years.
Our team partners with designers, development teams, and developers to develop bespoke applications for water purification and filtration.
David grew up in Howard County and currently resides in Montgomery County. After earning a degree in Chemistry from the University of Maryland, he and his father founded National Water Service over 30 years ago. Since then, we have proudly served the Mid-Atlantic region with superior products and exceptional service!
Business Services
- Bathtub installation
- Drain installation
- Faucet installation
- Faucet repair
- Garbage disposal installation
- Gas line installation
- Gas line repair
- Hot water recirculation pump installation
- Hot water recirculation pump repair
- Plumbing inspection
- Plumbing installation or replacement
- Plumbing repair
- Shower installation
- Sump pump installation
- Sump pump repair
- Toilet installation
- Water heater installation
- Water heater repair
- Water pipe installation
- Water pipe repair
- Water purification system cleaning and maintenance
- Water purification system installation
- Water purification system repair
- Salt delivery
Business Location & Hours
| Mon: | 7:00 AM - 5:00 PM |
| Tue: | 7:00 AM - 5:00 PM |
| Wed: | 7:00 AM - 5:00 PM |
| Thu: | 7:00 AM - 5:00 PM |
| Fri: | 7:00 AM - 4:00 PM |
| Sat: | Closed |
| Sun: | Closed |
Recommended Customer Reviews
""We lost our water on Sunday and could not reach our regular plumber. I searched online and found National Water Service along with several other companies. I based my decision to select them based on their customer reviews. My initial contact with Dave was met with an eagerness to help try and restore our water ASAP. Our system is electronic and he guided me through some procedures to attempt a ""reset"" over the phone ( BTW all done without getting $$ upfront) After several attempts it appeared that the mechanical pump and/or the control unit may have failed and they would have to schedule the repair for the next day as it was 6PM Sunday evening and the pump in my system was not a common pump and had to be picked up at a warehouse. They arrived Monday with the pump and controller but took the time to troubleshoot and diagnose the root cause (rather then just replace the pump and controller. ) The pump was tested and verified bad. Daniel and crew proceeded to replace the pump, tested the system after repair and cleaned up all work areas. He also made sure our lines were clear of mud/dirt/minerals that are often an issue after a well pump failure. All of my interaction from initial contact to the crew installing our pump were polite, professional and empathetic (a rare combination these days!) National Water Service will be our first call whenever we have a plumbing need in the future. ""
Always courteous, professional service. Reasonable prices. Would highly recommend this company.
Mark M.I have been working with National Water Service for over 20 years. They have always been knowledgeable, friendly, courteous, and reliable. I'm happy to recommend them to anybody looking for a water filtration system.
Their work seems to be good, but their billing practices leave much to be desired. It's really a shame.
Great service. Knowledeable & timely. Good prices. Worry free, no hassle experience,
Great service. Technician arrived in mask. Explained everything while he was completing the service. Finished in a timely manner.
William W.I knew we needed to do something about improving the quality of our city water supply for various reasons including how impurities effect our health and home. I felt it was an investment that I wished I had made earlier that may have also added to the longevity of several home appliances. Though a relation we considered the subject and scheduled a look and test of the water supply and what could be improved. We determined we wanted to improve water quality to the fridge as it makes ice and coffee and add instant hot water at the sink through a special faucet. All the equipment is installed and unobtrusive/neat and organized nicely. Did it for us but I suggest it's a great selling point if you ever sell your home. Let me highly recommend National Water Service to supply the right system and improve your Water Life....the rest is up to you.
Joseph J.NWS has been our go to water service company for 20 years. They've always arrive on time and work until the job is complete.
I have worked with the owner David, and his father Rene before him, on purifying the water at all our commercial locations. I have personally been using their services for over 20 years. The water is great, the installation is thorough and clean, the staff and maintenance crews are the best. You will never ever drink anything but reverse osmosis water for the rest of your life. Thanks team NWS!!
Jeanine W
National Water service did a great job, had the best price out of several companies, was the most recommended to us by other happy neighbors, and they also pointed us to a coupon to take advantage of when the technician came. Great company!

























