The short answer
Low water pressure usually traces to one of a few causes: a clogged aerator or fixture, a failing pressure-reducing valve (PRV), corroded galvanized pipe, or a leak in the service line. Whether it's one faucet or the whole house — and hot, cold, or both — tells you where to look.
First question: one fixture or the whole house?
The single most useful clue is scope. If only one faucet is weak, the problem is local — usually a clogged aerator or cartridge. If the whole house is weak, the cause is upstream: the PRV, the main, corroded piping, or a service-line issue. Narrowing this first saves a lot of guesswork.
The common causes
From easiest to most involved:
- Clogged aerator or showerhead — mineral buildup; often a five-minute clean or swap
- Worn faucet cartridge — affects one fixture's flow and temperature
- Failing pressure-reducing valve (PRV) — drops pressure house-wide as it ages
- Corroded galvanized pipe — decades of internal rust narrowing the pipe, common in older Atlanta homes
- A water service-line leak or partial blockage — low pressure plus a soggy yard or high bill
What's the failure mode to watch for?
Pressure that's been slowly dropping for years in an older home often points to corroding galvanized supply pipe — which won't improve until it's repiped. Pressure that drops suddenly can signal a failed PRV or a developing service-line leak. And too-high pressure is its own problem: it stresses fixtures and can void appliance warranties, which is why a PRV matters in both directions.
Test before you guess
A simple pressure-gauge reading at a hose bib tells us a lot. Healthy household pressure is typically 50-75 PSI; far below that points to a PRV, pipe, or supply issue worth diagnosing.
What's the next step?
If a quick aerator clean doesn't restore flow, we'll measure your pressure, find the real cause — PRV, pipe, or supply — and give you a flat-rate fix. For older homes with corroded galvanized pipe, we'll also explain whether a repipe is the lasting answer.
House-wide low pressure usually points upstream — a failing pressure-reducing valve, corroded galvanized supply pipe, or a service-line problem. A pressure-gauge test and a look at your pipe material quickly narrow it down.
Yes. Galvanized steel pipe corrodes internally over decades, narrowing the opening and choking flow. In older Atlanta homes this is a common cause, and repiping to copper or PEX restores pressure for good.
Terms in this guide
- Pressure-reducing valve (PRV)
- A valve that lowers and stabilizes incoming municipal water pressure to a safe level (typically 50–75 PSI). Too-high pressure stresses fixtures, water heaters, and joints, and can void appliance warranties.
- Repipe
- Replacing some or all of a home's supply (or drain) piping. Older Atlanta homes often have galvanized steel, polybutylene, or cast iron that corrodes or fails with age; a repipe swaps it for modern copper or PEX.
- Water service line
- The pipe that carries clean water from the city main (or your well) to your home. When it leaks or fails, it can cause low pressure, soggy spots in the yard, or a high water bill.
- Slab leak
- A water-line leak in or beneath the concrete foundation slab of a home. Common signs include a warm spot on the floor, the sound of running water with everything off, an unexplained spike in your water bill, or cracking in the slab.