What Causes Low Water Pressure? Top Reasons (and How to Fix It)

What Causes Low Water Pressure? Top Reasons (and How to Fix It)

There’s nothing like stepping into the shower only to be hit with a weak drizzle instead of the strong spray you were expecting. Or turning on the kitchen faucet to rinse dishes and wondering if water’s even coming out. If that sounds familiar, you’re probably dealing with low water pressure — and it’s one of the most common plumbing complaints we hear from Pittsburgh homeowners.

Whether the pressure dropped overnight or it’s been a slow, frustrating issue for a while, we’ve got you covered. In this post, we’ll break down:

• What causes low water pressure

• How to check for common issues

• Simple fixes you can try yourself

• And when it’s time to call in a pro

Let’s dive in and help you get your water flowing right again.

What Is Water Pressure (And Why Does It Matter)?

Water pressure is basically the force that moves water through your plumbing and out of your fixtures. It’s what gives you a strong shower, fills your washing machine quickly, and lets your faucets flow smoothly.

Most homes operate between 40 and 60 PSI (pounds per square inch). Anything much lower than that? You’ll start to feel the effects — slow filling sinks, toilets that take forever to flush, and overall weak performance from anything water-related.

Top Causes of Low Water Pressure in Your Home

1. A Partially Closed Shut-Off Valve

We’ve seen it more times than we can count — a shut-off valve that isn’t fully open. If you’ve recently had plumbing work done, or just moved in, it’s worth checking.

Start with your main shut-off valve, which is usually in your basement near where the water line enters. Then, check the meter valve, typically outside near your curb. Both should be fully open to allow normal flow.

2. Mineral Buildup in Faucets or Showerheads

Sometimes the problem isn’t with your pipes at all — it’s right at the fixture.

If just one faucet or showerhead has low pressure, hard water buildup might be the culprit. Over time, minerals can clog small openings in aerators and shower nozzles, restricting flow.

A quick DIY fix? Unscrew the aerator, soak it in vinegar overnight, and scrub it clean with a toothbrush. You might be surprised how well this works.

3. Old or Corroded Pipes (Common in Pittsburgh Homes)

If your house was built before the 1970s and hasn’t been re-piped, there’s a good chance you have galvanized steel pipes. These corrode from the inside over time, narrowing the passage for water.

Unfortunately, corrosion isn’t something you can just clean out. Replacing old pipes with modern PEX or copper is often the best (and only) solution for long-term performance and safety.

4. Hidden Leaks That Are Stealing Your Water

A leak in your plumbing system doesn’t always show up as a puddle under the sink. Sometimes, the leak is hidden in a wall, crawlspace, or underground — slowly draining water pressure and driving up your bill.

Watch for signs like:

• Unexplained spikes in your water bill

• Damp spots or water stains on walls and ceilings

• The sound of running water when everything is off

If you're suspicious, don’t wait — small leaks can turn into big repairs fast.

5. A Failing Pressure Regulator

Not all homes have one, but if yours does, a pressure-reducing valve (PRV) could be the issue. It’s usually located near your main water line and helps regulate safe pressure throughout your system.

If it’s malfunctioning, you might see either a sudden drop or surge in pressure. This is definitely a “call the plumber” situation — we can test it and swap it out if needed.

6. Blocked or Partially Clogged Pipes

If your home has older pipes or has gone years without a good plumbing flush, sediment or rust buildup could be slowing things down. Worse yet, if tree roots have found their way into your sewer lines, they can restrict water flow too.

Unlike a clogged aerator, this isn’t something you’ll fix with vinegar. We can use cameras and pressure testing to locate the blockage and recommend the best repair.

How to Figure Out What’s Causing the Problem

Before calling a plumber, here are a few steps you can take to narrow things down:

• Check all faucets. Is it just one area or the whole house?

• Try cold vs. hot water. If only hot water is weak, it could be a water heater issue.

• Ask your neighbors. If they’re also experiencing low pressure, it might be a city-wide issue.

• Test the pressure. You can get a water pressure gauge at most hardware stores. Attach it to an outdoor spigot — anything below 40 PSI is on the low side.

These steps can help you determine if the problem is small and local, or something that needs a professional diagnosis.

Quick Fixes You Can Try on Your Own

Not every pressure problem requires a plumber. Here are a few safe DIY fixes you can try first:

• Clean your faucet aerators and showerheads

• Make sure all shut-off valves are fully open

• Flush your water heater to remove sediment

• Replace flexible supply lines if they look kinked or old

Sometimes, the fix is as simple as turning a handle or clearing a little buildup. But if you’ve tried these and nothing’s improved, don’t keep guessing — give us a call.

When It’s Time to Bring in the Pros

We always recommend calling a licensed plumber when:

• You suspect pipe corrosion or hidden leaks

• The problem affects multiple fixtures or the whole house

• You have extremely low pressure (under 30 PSI)

• Your pressure regulator is acting up

• You want peace of mind that the issue’s been properly diagnosed

At Revelation Plumbing, we’ve handled every kind of water pressure issue imaginable — from small fixture clogs to full-home repiping. We know what to look for, how to find the root of the problem, and how to fix it right the first time.

Serving Pittsburgh Homeowners with Water Pressure Solutions That Last

If you're in the Pittsburgh area and dealing with weak water pressure, don’t put up with it any longer. It’s not just an inconvenience — it could be a warning sign that something more serious is happening behind your walls or under your foundation.

Let Revelation Plumbing come take a look. We offer honest advice, upfront pricing, and real solutions you can count on.

📞 Call or text us today at 412-518-7170Proudly serving Pittsburgh and surrounding communitiesFriendly. Fast. Local.

Revelation Plumbing – Where Your Clog Meets Its Maker