The Town of Herndon buys its water from Fairfax Water, mainly from the Corbalis plant on the Potomac, where hardness runs about 70 to 185 mg/L and averages roughly 7.5 grains per gallon. That's enough to scale water heaters and fixtures. Call the number on this page to be connected with a local plumber in Herndon.
Herndon's water and housing
Inside town limits, the Town of Herndon's Department of Public Works runs the water and sewer system, buying finished water from Fairfax Water. The Town's report says Herndon receives water mainly from the James J. Corbalis plant, where Fairfax Water's analyses show total hardness of about 70 to 185 mg/L. Herndon-addressed homes outside town limits are generally on Fairfax Water directly; the same range applies.
The median Herndon home was built around 1983. Many houses have basements or garages with the main near the water heater, which is the natural spot for a softener. The Town reports no lead service lines in its inventory.
| Option | Good fit when | Keep in mind |
|---|---|---|
| Metered salt softener | You want spot-free glass and less scale in the water heater | Needs a drain, an outlet and regular salt |
| Softener with carbon prefilter | Disinfectant taste bothers you, or you want to protect resin | Carbon media needs periodic replacement |
| Salt-free conditioner | No drain is nearby and you want low maintenance | Minerals stay in the water; less visible benefit |
| Repair existing unit | Tank and resin are sound, valve or seals failed | Old timer units waste salt |
Signs to look for
- Scale on faucets and shower doors
- Spotted dishes and a film in the dishwasher
- Water heater noise or reduced output
- Brine tank full of water, or salt that never goes down
- Tankless heater error codes tied to scale on the heat exchanger
When you call
The number on this page is a free referral line, not a plumbing company. It connects you with an independent plumber who works in Herndon. Mention whether you're inside town limits, how many people live in the home, and where the main and water heater sit. A photo of any existing softener's label and valve helps the plumber bring the right parts.
Timing and seasonal notes
The Town's report lists chlorine as the disinfectant, and Fairfax Water switches between chloramines and free chlorine during the year, with free chlorine generally in spring. If taste changes then, it's the disinfectant, not the softener. Backflow devices in town, including irrigation, must be tested every year and reported to Town Building Inspections, so plan softener plumbing to leave those assemblies accessible. Inside town limits, Herndon's Building Inspections office issues plumbing and gas permits; outside town limits, Fairfax County handles them.
Water Softeners & Filtration questions in Herndon
How do I turn mg/L or ppm into grains per gallon?
Do I need a permit to put in a water softener?
Should outdoor spigots and irrigation skip the softener?
How often does a softener need salt and service?
More plumbing services in Herndon
Water Softeners & Filtration nearby
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