Most of what gets written about residential pipes concerns the sewer lateral — the line taking waste away. The water service line, bringing clean water in, gets far less attention until it fails. It behaves quite differently, and it is worth understanding separately.
How it differs from your sewer line
The critical distinction is pressure. Your sewer lateral moves waste by gravity, so when it fails the water backs up toward the house and you find out immediately and unpleasantly.
A water line is under constant pressure. When it fails, water is pushed out into the surrounding soil continuously, twenty-four hours a day. Nothing backs up. Nothing floods, at first. You simply pay for water that never reaches a tap — often for months before anyone notices.
Signs your water service is failing
- A water bill that rose sharply with no change in household usage
- The meter continues to move with every fixture in the house shut off
- Noticeably reduced pressure at the taps, particularly a gradual decline
- A patch of ground between the meter and the house that stays soggy during dry weather
- Discoloured or rusty water, which can indicate corroding galvanised pipe
- The sound of running water with nothing turned on
Who is responsible for which part
In Montgomery and Prince George’s County the general division is that WSSC Water maintains the main and typically the connection up to the meter, while the property owner is responsible for the service line from the meter to the house.
That privately owned section is where most failures land, and it is the part homeowners are frequently surprised to learn they own. If diagnosis shows the fault sits on the public side, we will tell you that rather than sell you a repair you do not owe.
What typically fails, and why
Older Maryland homes often have galvanised steel service lines. Galvanised corrodes from the inside, narrowing the bore and eventually perforating — which is why declining pressure and rusty water often appear together.
Copper is more durable but vulnerable to pinhole leaks, particularly where soil chemistry or stray electrical current accelerates corrosion. Modern installations use HDPE or PEX, neither of which corrodes.
Replacing it without a trench
This is the part most people do not realise: trenchless is not only for sewers. A water service can be replaced by pipe bursting exactly as a sewer lateral can — a bursting head is pulled through the old line, fracturing it outward while drawing new HDPE into place behind it.
Two compact pits instead of a trench across the front garden. That matters here, because the water service usually takes the shortest route from the street to the house — which is to say, straight through the front lawn, and frequently under the driveway, path or porch.
The new HDPE line is seamless, will not corrode, and is rated well beyond the life of what it replaces.
Repair or replace?
A single pinhole in an otherwise sound copper line is a spot repair. A galvanised line that has corroded to the point of pressure loss is not — patching one perforation in a pipe that is failing along its whole length simply relocates the next leak.
Age, material and how many times it has already been repaired are the deciding factors. If you are on your second or third leak in a few years, you are paying for a replacement in instalments.