Why is my water pressure low?
Most low-pressure problems trace back to one of a few culprits: clogged faucet aerators or fixtures, a failing pressure regulator (PRV), a partly closed valve, a hidden leak, or old corroded pipe restricting flow.
The good news is that low pressure is a symptom with a short list of common causes. With a couple of quick observations, you can usually narrow it down — and sometimes fix it yourself before it ever needs a service call.
Whole house, or just one fixture?
This is the single most useful question to answer first. Where the weak pressure shows up tells you whether the problem is local to one spot or affecting your entire system.
- One fixture is weak: the cause is usually local — a clogged aerator, a worn cartridge, or a partly closed shutoff valve under that sink or behind that toilet.
- Every fixture is weak: the cause is upstream and affects the whole home — think main valve, pressure regulator, or a leak.
- Only hot water is weak: the issue is often at the water heater — its shutoff valve or sediment buildup inside the tank.
Common causes of low water pressure
Once you know whether it's local or whole-house, these are the usual reasons pressure falls off:
- Clogged aerators and fixtures: mineral buildup from hard water clogs the little screens on faucets and showerheads.
- Failing pressure regulator (PRV): when this valve fails, it can choke pressure to the whole house.
- A partly closed valve: the main shutoff or a meter valve that isn't fully open quietly throttles flow.
- A hidden leak: water escaping before it reaches your taps lowers pressure — including a slab leak under the foundation.
- Corroded old pipe: aging galvanized or scaled pipe narrows from the inside, steadily reducing flow over the years.
- A supply-side issue: sometimes it's the municipal supply or a recent repair upstream, not your plumbing at all.
Quick checks you can do yourself
A few simple checks solve a surprising number of low-pressure complaints — and if they don't, they help your plumber zero in faster.
- Clean the aerator: unscrew the tip of a slow faucet, rinse out the mineral grit and screen, and reattach it — often an instant fix for one slow tap.
- Check the main shutoff: make sure your home's main valve and the fixture's local shutoff are turned fully open.
- Look at the PRV: if your home has a pressure regulator (often near the main line), note whether pressure problems started recently — a clue it may be failing.
- Rule out the water heater: if only hot water is weak, check the heater's shutoff valve is fully open.
Know when to stop
Cleaning an aerator or checking a valve is homeowner-friendly. Adjusting a pressure regulator, opening pipe, or chasing a hidden leak is not — those need a licensed plumber with the right tools so you don't trade a small problem for a big one.
When low pressure means something serious
Sometimes weak pressure is the first symptom of a bigger problem. If the easy checks don't help — especially with a sudden, unexplained drop — it's worth looking deeper.
A persistent whole-house drop can point to a hidden leak. In Florida's slab-on-grade homes, that can mean a slab leak, which we find with professional leak detection. And if old, corroded pipe is steadily strangling flow throughout the house, it may be time to consider whether a repipe makes sense.
A higher bill plus low pressure
Low pressure paired with a higher-than-usual water bill is a classic hidden-leak signal. If you see both at once, it's worth having it checked before the leak does more damage.
How Anna's helps
When the simple fixes don't restore your pressure, we find the real cause instead of guessing. We're a woman-owned, licensed and insured local team, and we diagnose low-pressure issues — from a failing regulator to a hidden slab leak — across Melbourne and the Space Coast.
Explore our plumbing services, or if you've already been quoted a major repair, get a free second opinion first. Every recommendation is backed by our 365-Day Money-Back Guarantee.