Start by sorting one fixture from the whole house
Low pressure means different things depending on where you see it. If only the kitchen faucet is weak, the problem is in that faucet. If every tap and the washing machine fill slowly, something upstream is restricting the flow to the whole house.
Open a tap in each bathroom, the kitchen and an outdoor spigot, and compare. Hot only and cold fine points at the water heater side. Both weak everywhere points at the supply, the meter valve, the pressure-reducing valve or a leak.
What the pattern tells you
Callers describe low pressure in a few recognizable ways. Each one narrows the list of causes.
One faucet is weak, the rest are fine
A clogged aerator or a partly closed stop valve under that sink is the usual cause.
Hot water is weak, cold is normal
Sediment in the heater or a half-open valve on the hot side. The county does not control the temperature or flow inside your home.
Whole house is weak all day
Look at the pressure-reducing valve, the main shutoff and the meter valve, then test for a leak.
Pressure drops when a second fixture opens
Often a restriction in the supply line or a tired valve that cannot keep up with demand.
Pressure swings or the pipes bang
A failing pressure-reducing valve can let pressure surge, and a water hammer sound follows.
The pressure-reducing valve is the usual suspect
Utility water arrives at higher pressure than household fixtures should see, so many homes have a bell-shaped brass valve near where the main line enters the house. It steps the pressure down. Over the years the internal spring and diaphragm wear, and the valve can drift low, stick or stop passing water well.
Gwinnett County Water Resources states on its pressure and temperature page that low pressure is most commonly due to issues with the home pressure-reducing valve, sometimes called a relief valve, and that these valves are the homeowner's responsibility. The county also says its staff do not investigate or repair them.
A plumber can read the actual pressure by threading a gauge onto an outdoor spigot, which is a quick way to see whether the valve is passing a sensible number. We cannot give you a typical figure for Gwinnett, so ask the plumber to tell you the static reading and what the valve is set to.
Checks you can do in about twenty minutes
These need no tools beyond a screwdriver and a flashlight. Do them in this order.
Check the front spigot
The county page tells homeowners to check the front spigot. Open it fully, note how strong the flow is, then compare it to an indoor tap. A big difference helps a plumber find where the loss happens.
Look at the house main valve
A gate or ball valve near where the line enters the house may have been bumped partly closed after a repair. A ball valve should sit with the handle parallel to the pipe when open.
Check the meter valve
The meter is in the front yard under a metal cover. The valve on the house side should be fully open. If you are not sure how it works, leave it alone and call.
Clean the aerators
Unscrew each faucet tip, rinse out grit and soak it in vinegar. The county also gives out a free low-flow kit that includes faucet aerators, so a fresh one is easy to get.
Look for a hidden leak
Shut off all water use, then watch the meter dial. Gwinnett says nothing on the meter should move when no water is being used.
Likely cause and who deals with it
Not every low pressure problem is the same kind of repair. This table sorts causes by where they sit.
| Cause | Where it sits | Who handles it |
|---|---|---|
| Clogged aerator or showerhead | End of one fixture | You, in minutes |
| Partly closed stop or main valve | Under a sink or at the house main | You, or a plumber if the valve is stuck |
| Worn pressure-reducing valve | Near where the line enters the house | Homeowner, per Gwinnett Water Resources |
| Leak in the yard line | Between meter and house | Homeowner, plumber to locate and repair |
| Problem on the county side of the meter | Water main or meter | Gwinnett Water Resources |
Suwanee note: where the county stops and you start
Gwinnett County Water Resources says it maintains the water main, the small pipe from the main to your meter and the meter itself. Everything on your side of the meter, including the line to the house, belongs to you. A soft, wet patch in the yard between the meter and the house is therefore your repair, not the county's.
The county's leak detection page says to check the meter after two hours without water use and describes the meter as sitting in the front yard under a metal cover. If the dial moves when every tap is off, you have a leak, and a weak shower may be the first sign of it.
If the pressure trouble is on the county side, DWR's 24/7 dispatch line is 678.376.7000. Gwinnett also lists a flow test for customers when the issue is on the county side, so ask when you call. For leaks on your side, the county's customer FAQ says water and sewer adjustments are offered on eligible accounts and that Customer Care can explain the steps, so keep the plumber's invoice.
Fix it yourself or hire a plumber
Cleaning aerators is a homeowner job. Pressure valves and buried lines are not.
Safe to do yourself
- Clean aerators and showerheads
- Open stop valves fully
- Run the meter test
- Read the outdoor spigot flow
Call a plumber for
- Testing and replacing the pressure-reducing valve
- Locating a leak in the yard line
- Replacing a seized main or stop valve
- Corroded galvanized pipe that has narrowed inside
When the pipes themselves are the problem
In older homes with galvanized steel supply lines, mineral and rust buildup narrows the inside of the pipe over decades, and pressure falls even when the valve is fine. No cleaning product fixes that. The usual answer is replacing the affected run, which is covered under repiping.
A leak in the buried line from the meter is a separate repair. Our water line repair page explains how that line is located and replaced, and leak detection covers the tools used when the leak is not visible. Neighbors in Lawrenceville and Duluth see the same pattern, where a valve gets the blame first and the hidden leak turns up second.
According to Gwinnett County Water Resources, low water pressure is most commonly caused by the home's pressure-reducing valve, and those valves are the homeowner's responsibility. The county suggests checking the front spigot first to see whether the problem covers the whole house or only one line.
Low water pressure questions
Not inside the home. Gwinnett County Water Resources says the home pressure-reducing valve is the homeowner's responsibility and that the county does not send personnel to investigate or repair it. If the problem is on the county side of the meter, call the 24/7 line at 678.376.7000.
Open the front spigot and compare it with an indoor tap. Then check that the main and meter valves are fully open and clean the aerators. Those checks cost nothing.
That points to the water heater side, such as sediment or a partly closed valve on the hot outlet. The county says it does not control the water temperature in your home.
Yes. A leak between the meter and the house takes water before it reaches your taps. Do the meter test with every fixture off, and watch for movement on the dial.
Gwinnett Water Resources offers free low-flow home retrofit kits at its Central Facility. The kit includes a low-flow showerhead, faucet aerators and toilet leak dye tablets.