Two things shape plumbing work in Herndon: which jurisdiction you are in, and whether your house went up before or after the mid 1990s.
The incorporated Town of Herndon has its own government and permit office. Most of 20171 and part of 20170, the corridor build-out, is Fairfax County. That decides who permits and inspects work that needs it, which includes gas water heater replacement and any repiping.
Identifying and Replacing Polybutylene Piping in Herndon Homes
Polybutylene was installed in American homes between 1978 and mid 1995, which overlaps the decade when much of Herndon filled in. That makes the three minute check worth doing.
Look at the main water entry and under a bathroom sink. Grey plastic with crimped metal rings, sometimes stamped PB2110, is polybutylene. It fails at fittings without warning and it makes a house harder to insure. What to do about it is here.
White rigid plastic is CPVC, common in 1990s work and generally fine. Red and blue flexible is PEX, modern. Copper is copper, and in a house this young it has decades left.
In the older town blocks you may find galvanized steel, which is dull grey, threaded, and magnetic. It narrows from the inside, so a slow decline in flow over years is the sign.
What we actually get called for
Water heaters reaching the end. Tanks last eight to twelve years here, and in a neighborhood built within a few years the water heaters age out together. A replacement runs $2,000 to $4,800 installed. The maintenance that extends the one you have is here.
Angle stops and supply lines. The small shutoff valves under sinks and behind toilets, and the braided lines to them. These are the most common cause of an indoor flood in a house of this vintage, and replacing them before they fail is inexpensive.
Toilet fill valves. Builder-grade parts at twenty five to thirty years. A silently running toilet wastes more water than people think; ten drops of food colouring in the tank and a ten minute wait settles it.
Pressure reducing valves. They wear out in ten to fifteen years, which is where a lot of Herndon houses sit. A failed one puts the whole house at street pressure, which stresses every fitting and makes fill valves fail early. A $12 gauge on a hose bib tells you; replacement runs $500 to $994.
Hidden leaks. A leak search runs $200 to $470, middle around $330, including opening the wall where the evidence points. Do the meter test first. The full method is here.
Drains. $200 to $800 for one fixture, middle around $430; main line $860 to $1,600.
Hard water, and the tankless question
This area’s water is moderately hard to hard. That scales the inside of a tank water heater and is genuinely hard on a tankless unit, where both Navien and Rinnai require annual descaling in writing and both exclude scale damage from the warranty. A flush runs $79 to $365, most between $100 and $200. What your utility publishes, and the three real options, is here.
Before winter
Disconnect every hose, including from frost-free spigots, because a hose attached defeats the frost-free design entirely and that is the pipe that floods a wall in April. Find your main shutoff and confirm it turns. The rest of the list is here.
SwiftPro handles plumbing across Herndon, in the town and the county. Call (703) 997-9757, book online, or see our plumbing services.
