What To Do About Low Water Pressure

Showers so weak they leave you more aggravated than relaxed. Faucets that can barely wash your hands, let alone the lasagna dish. When your home's water supply exhibits all the energy of a dying sloth, it's time to get serious about low water pressure. The causes are varied, but with a bit of determination, it is possible to remedy this most annoying of household problems.

If you want to be really literal about things, spend a few bucks on a water pressure gauge to check the actual pressure in the pipes. Opinions and tastes differ, but generally, pressure should be somewhere between 45-80 psi. Pressures higher than this may damage fixtures.
You might just be at the wrong place at the wrong time: heavy neighborhood or household water use during "peak periods" (morning showers before work/school, evening dishes) could drop water pressure to the point of anger. If possible, try changing around your schedule to see if anything changes.
On a well? It could be that the air bladder (pressure tank) and pressure switch were set incorrectly - check against manufacturer and/or installer specifications. The pump should also be checked: these can become clogged with sediment and debris, requiring cleaning and maintenance. If you're unfamiliar with the well's operation, let a professional inspection determine if there are any issues.
Check each faucet in the house to see if the pressure problem is isolated to only a few fixtures. Run hot and cold water separately: both should have roughly the same pressure. If the hot water is noticeably less, there's likely an issue with the water heater - the shut-off valve may not be fully open, or tank sediment could be restricting flow to the house. For the latter, flushing the heater should help.
If it's only the shower head and/or a faucet that are weak, they may just need a good cleaning. To clean a shower head or faucet aerator, simply soak them in vinegar. Aerators are easily removed from faucets, as are shower heads (you can also tie a bag of vinegar around the head without having to remove it). Use an old toothbrush to remove any particularly stubborn gunk. Be sure to run water through the faucet without the aerator before putting it back on. If pressure problems persist, the problem lies elsewhere.
Do problem-fixtures have their own shut-off valves? Check them to make sure they're fully open.
Water softeners can also cause low water pressure. If yours doesn't have an obvious bypass valve or bypass feature, have a plumber divert water around it to see if house pressure improves. If it does, the softener probably needs repair or replacement.
Repairs on water mains can introduce and/or dislodge dirt and sediment into the supply. This will, of course, end up in your aerator. If you know repairs are taking place, remove aerators and give the pipes a good flush when your water is turned back on.
Rust inside iron water pipes can easily break loose and end up clogging aerators and valves. Galvanized steel pipes will also corrode, potentially leading to the same problems. Corrosion in these pipes often accumulates, leading to reduced flow. Unfortunately, you'll either just have to accept the low-pressure, or replace these archaic pipes.
If, even after cleaning the aerator, you still have an isolated pressure issue with a faucet, the stem or cartridge inside could be plugged with debris, or have some other critical issue. If you know the make and model of the faucet, try finding a replacement. If the faucet is a mystery, contact our customer service team with photos and measurements - we may be able to help.
Just as the individual shut-off valves at fixtures can be turned just enough to restrict flow, so too can the shut-offs outside the house. Check the main shut-off, usually found on an outside wall, the basement, or a utility room. Then, check the shut-off at the water meter (which should be in a box between the house and sidewalk, or in the basement).
Some cities require that Pressure Reducing Valves (PRV) be installed on the water supply to locations that experience high pressure (usually above 80 psi). These are cone or bell-shaped devices most often found after the water meter and before the water heater. It's possible that yours is set too low. If your investigation has so far proved unfruitful, have a plumber inspect the PRV.
The final suspect around your property can be among the most challenging to pinpoint: a leak. Sure, there could be a running toilet or an obvious puddle somewhere... but you probably would've noticed that before. Check out our handy guide to expose even the most elusive leaks, and get them taken care of - even if they aren't behind your pressure problems.
If, after your careful and determined troubleshooting, there's still not enough kick in your water supply, it's time to survey the neighbors. Are they experiencing the same kinds of issues? If so, there's a problem with the municipal supply that the city or water service needs to deal with.
...but what if your neighbors are doing just fine, reveling in their effective, comfortable, joy-bringing shower? If nothing seems to explain or remedy your low water pressure, you may need to start looking into setting up a booster pump, or constant pressure system. As you might have gathered, these pumps boost water pressure, and keep it steady even when there's high demand. Hire a plumber, or consult the relevant city department to find out if a permit is necessary, and what else is required in the installation (often a pressure tank, backflow preventer and/or PRV).