Where do I start with low water pressure?
Start by finding out whether it's one faucet, only the hot water, or the whole house. Run a few faucets, inside and out, hot and cold, and compare.
If it's one fixture, look there. If it's the hot water everywhere, look at the water heater. If it's everything, look at the main line and the supply.
Why is one faucet or showerhead weak?
Usually it's minerals or grit clogging the screen at the tip of the faucet (the aerator) or the holes in a showerhead.
Most aerators unscrew by hand. If one's stuck, wrap it in a rag before the pliers go on. A soak in white vinegar clears most crusty screens. It's a 5-minute job, and it's the fix we'd try first.
Still weak? The small valve under the sink (the stop valve) may be partly closed. Open it gently. Old ones can start leaking when turned, so if yours drips, turn it back and call us.
The part inside that controls the flow (the cartridge) can clog or wear out too. On a newer faucet, replacing the cartridge is the cheaper fix. If nobody stocks one for yours, put the money toward a new faucet.
Why is only my hot water pressure low?
Weak hot water at every faucet, with normal cold, usually points to the water heater or the valves near it. The shutoff on the cold line into the heater may be partly closed, or a valve may be failing. If only one faucet's hot side is weak, it's usually that faucet.
On a tank heater, bits of scale and sediment can break loose and clog hot-side aerators and cartridges. On a tankless unit, scale or a clogged inlet screen can restrict flow. Flushing or descaling is routine water heater service.
Why did the pressure drop across the whole house?
A sudden drop across the whole house usually means a closed valve, a new leak, or a change on your water utility's side. Check the main shutoff first. After any plumbing work, make sure it's all the way open.
Then ask a neighbor. If their pressure dropped too, the utility may be working on a main, or demand may be high in a dry spell. If it's only your house, look for a leak.
A clogged whole-house water filter can choke every faucet at once, and a fresh cartridge is often the whole fix. If you change it yourself, close the valves and release the pressure before opening the housing.
How can I tell if a hidden leak is the problem?
If you're on city water, your meter is the easiest test. Turn off everything that uses water, including the ice maker, irrigation and any softener that flushes itself. Watch the small leak indicator for a few minutes, then check the reading again 2 hours later, with no water used.
If it moved, close the main shutoff at the house and look again. If it still moves, the leak is likely in the line from the meter.
A toilet leaking into its bowl moves the meter too, but a leak that small won't usually weaken your pressure. A broken line will, and it needs attention right away. Finding a leak you can't see is its own job: leak detection.
What does a pressure-reducing valve do?
A pressure-reducing valve (PRV) cuts the higher pressure from the street down to what your plumbing can handle. Not every home has one. Where there is one, it's usually a bell-shaped brass valve on the main line. Look near where it enters the house, or out by the meter.
When its parts wear out, the pressure can sag or creep too high.
We like to see house pressure in the 40 to 60 psi range. A hardware-store gauge that screws onto an outdoor faucet will tell you where yours is. Read it with nothing else running, before anyone touches the adjusting screw. If it's off, we'll tell you whether the valve needs adjusting, repairing or replacing.
Can old pipes cause low water pressure?
Yes. In older homes, galvanized steel pipe rusts and collects minerals inside until the opening is much smaller than it was. The pressure coming in can be fine. The water just can't get through fast enough, so it drops off as soon as a faucet opens.
The drop is usually gradual, often worse upstairs and at the far end of the house, sometimes with rusty or discolored water.
Flushing won't clear pipe like that. Some companies line the old pipe instead. The fix we trust is replacing it: the worst sections or the whole house (repiping), usually with copper or PEX. If most of the house is still galvanized, we'd think hard before patching one run at a time. The rest is aging the same way.
What if my home is on a well?
On a well, low pressure usually points to the pressure tank, the pressure switch or the pump. The switch tells the pump when to run. The tank stores water under pressure, so the pump doesn't start every time a faucet opens.
Some rise and fall as the pump cycles is normal. If the pressure swings quickly while one faucet runs, or the pump clicks on every few seconds, the tank has likely lost its air charge. Knock on the top. It should sound hollow, not full.
This is where we'd have you stop. The switch and pump run on live power, often at a higher voltage than a regular outlet. Don't open the switch cover.
Pressure tanks and well house plumbing fall under our well house work. Wiring is electrical work, done by licensed and insured techs, and the same call covers it. Pump work down in the well takes a separate state license, and we'll tell you if that's the problem.