You turn on the shower and get a trickle. You run the kitchen tap and nothing comes out. When water pressure drops without warning in a Clarksburg, MD, home, the cause is rarely obvious, and the list of possibilities is long enough to be genuinely confusing.
This guide walks you through the six most common causes of low or no water pressure for homeowners in Clarksburg and the surrounding Montgomery County cities, Gaithersburg, Germantown, Bethesda, Potomac, Olney, and Poolesville. By the end you will know which problems you can check in five minutes yourself and which ones require a licensed plumber before they get expensive.
Is It Your Home or the WSSC System?
The first question to answer is whether the problem starts at your property line or upstream of it.
WSSC Water, the utility that supplies most of Montgomery County, operates a distribution system where static pressure can range from roughly 40 psi to well above 80 psi depending on your neighborhood’s elevation and proximity to storage tanks. When a main breaks or WSSC performs scheduled maintenance, pressure drops affect multiple homes on the same block at the same time.
Check two things before touching anything in your house. First, call a neighbor and ask whether their pressure is also down. Second, check the WSSC Water outage map or call their 24-hour emergency line at 301-206-4002. If your neighbor has the same problem and WSSC confirms an active main break or maintenance event in your area, the fix is on their end. Pressure returns when the repair is complete, usually within a few hours.
If your neighbor’s water is fine and WSSC shows no active issues, the problem is inside your property. That is where the six causes below come in.
Six Causes of Low Water Pressure in Your Home
1. A Shut-Off Valve That Is Not Fully Open
Every house served by WSSC has a main shut-off valve, typically located in the basement or utility room near where the water line enters the foundation. A second valve sits at the meter, usually outside near the street.
Either valve can be partially closed by accident: after a past repair, after a city technician worked nearby, or simply because the valve aged and stiffened into a half-open position. Even a valve that is 15 to 20 percent closed creates a noticeable restriction in flow.
Check the valve in your basement first. If it is a ball valve, the handle should be parallel to the pipe, not perpendicular to it. If it is a gate valve, turn it fully counterclockwise until it stops. Restore it to fully open and test a faucet immediately. This fix costs nothing and takes about two minutes.
2. A Failing Pressure-Reducing Valve
Homes in Montgomery County that receive supply pressure above 80 psi are required by WSSC plumbing code to have a pressure-reducing valve (PRV) installed on the main service line. The PRV steps municipal pressure down to a safe range, typically 50 to 65 psi, before water reaches your fixtures.
PRVs last roughly 10 to 15 years. When one fails, it usually does one of two things: it freezes in the mostly closed position, starving the whole house of water, or it allows full system pressure through, which hammers pipes and stresses appliances. A sudden, house-wide loss of pressure where every fixture is affected equally is the clearest sign of a failed PRV.
A plumber can test the PRV’s output with a pressure gauge in about 15 minutes. If the reading is well below the set point, replacement is straightforward. Do not try to crank the adjustment screw yourself without a gauge in hand, because over-pressurizing your home’s plumbing causes real damage.
3. Mineral Buildup in Pipes or Fixtures
WSSC Water sources from the Potomac River, and while the treated supply meets federal quality standards, the water is moderately hard. Over years of use, calcium and magnesium deposits accumulate inside older galvanized steel pipes, slowly narrowing their interior diameter the way plaque narrows an artery.
Older neighborhoods in Bethesda, Potomac, and parts of Germantown, where homes built in the 1960s and 1970s still have original galvanized supply lines, see this problem regularly. The pressure loss develops gradually, and homeowners often adapt to it without realizing the baseline has dropped significantly.
Mineral deposits also clog aerators on faucets and showerheads. Before calling a plumber, unscrew the aerator on the low-pressure faucet and inspect the screen. If it is coated in white or gray scale, soak it in white vinegar for 30 minutes, scrub it clean, and reinstall it. If that single fixture improves but others remain weak, the issue is deeper in the supply line.
If your home still has galvanized steel pipes and multiple fixtures run weak, the pipe itself is the bottleneck. Replacement with copper or PEX restores full pressure and eliminates the risk of sediment contaminating your water. Our water line repair and replacement service covers both traditional and trenchless options for exactly this situation.
4. A Hidden Leak in the Supply Line
A leak anywhere between the water meter and your fixtures removes pressure from the system before the water reaches your tap. Small leaks inside walls or under floors are quiet and invisible for months. A leaking underground supply line between the meter and your foundation is even harder to spot.
Three signals point to a hidden supply leak. Your monthly water bill climbs for no obvious reason. You hear water running in the walls or floors when every fixture is off. Most usefully, you can use your water meter directly: shut off every fixture and appliance in the house, then go outside and look at the meter. If the dial or digital readout is still moving, water is leaving the system somewhere.
A supply leak that has been running long enough to drop pressure has already saturated the surrounding soil or structure. The longer it runs, the larger the repair bill. Underground supply line leaks in particular require excavation unless a trenchless repair method is suitable. Clarksburg Plumbing uses state-of-the-art leak detection technology to locate the source without unnecessary digging before any work begins.
5. Corroded or Damaged Main Water Line
The main water line connects WSSC’s meter at the street to your home’s interior plumbing. Most homes in Montgomery County built before 1980 have lines made from galvanized steel or, in some older properties, lead. WSSC banned lead service lines in 1954, but galvanized lines installed after that date still corrode from the inside over decades of use.
Corrosion shrinks the effective diameter of the pipe and can eventually cause it to fail. The clearest external sign is wet or unusually green patches of grass in your yard, especially along the path from the street to the house. You might also notice discolored water, a sudden spike in water bills, or pressure that drops whenever two or more fixtures run simultaneously.
A corroded main water line will not repair itself. Whether the right solution is a spot repair or a full main water line replacement depends on the age, material, and condition of the pipe. Copper, PVC, and PEX are the materials used in replacements today, and each has a lifespan measured in decades rather than years.
6. Water Heater Sediment
Low hot-water pressure from every fixture in your home, while cold water runs fine, usually points to the water heater. Sediment, primarily calcium and mineral deposits from WSSC’s Potomac-sourced supply, settles to the bottom of tank-style heaters over time. Eventually it clogs the inlet or outlet connection enough to restrict flow.
A plumber can flush the tank to clear light sediment. Heaters that have never been flushed and are more than eight to ten years old often need replacement rather than maintenance, because heavy sediment calcifies around the heating element and shortens the unit’s remaining life. Our residential water heater service covers diagnosis, flushing, repair, and replacement for both tank and tankless systems.
When to Call a Plumber Instead of Waiting
Some pressure problems are inconvenient. Others indicate active water damage happening inside your walls or under your foundation right now. Call a plumber the same day if:
- Every fixture in the house has low or no pressure and the main valve is fully open.
- Your water meter shows movement when all fixtures are off.
- You see wet spots, soft drywall, or water stains near supply lines.
- Water is discolored or has an unusual odor alongside the pressure drop.
- Pressure drops whenever two fixtures run at the same time.
Any of these patterns means a leak, a failed PRV, or a corroded line. None gets better on its own.
Why Montgomery County Homeowners Call Clarksburg Plumbing
Clarksburg Plumbing has been serving Clarksburg, MD, and surrounding Montgomery County communities for over 15 years. The company holds a WSSC Journeyman Plumber License, a WSSC Gas Journeyman License, and earned nationwide WBENC certification in 2019. Labor is guaranteed for one year. Underground services carry a three-year warranty, and water line materials are backed by a lifetime guarantee.
The team is available 24 hours a day, seven days a week. Estimates are free, and pricing is transparent before any work begins. Call 301-972-2223 or book online to schedule a diagnosis.
Frequently Asked Questions
What is normal water pressure for a home in Clarksburg, MD? The WSSC plumbing code requires a pressure-reducing valve on any home where supply pressure exceeds 80 psi. For comfort and to protect appliances, most plumbers set the PRV to deliver between 50 and 65 psi inside the home. If you want to check yours, a water pressure gauge that threads onto an outdoor hose bib costs about $15 at any hardware store.
Can low water pressure damage my plumbing or appliances? Low pressure itself rarely damages pipes, but the underlying cause often does. A corroded main line contaminates water. A hidden leak saturates framing and promotes mold. A sediment-clogged water heater burns out prematurely. Treat the pressure drop as a warning, not just an annoyance.
Does Clarksburg Plumbing serve cities beyond Clarksburg, MD? Yes. Clarksburg Plumbing serves Gaithersburg, Germantown, Bethesda, Potomac, Olney, Poolesville, Boyds, Damascus, Rockville, and other Montgomery County communities. Call 301-972-2223 to confirm service to your address.
