Why Is My Water Pressure So Low? Common Causes and What to Do

A weak trickle from the shower. A faucet that takes forever to fill a pot. A garden hose that barely reaches the flower bed. Low water pressure is one of the most frustrating plumbing problems a homeowner can deal with — and it rarely fixes itself.

The tricky part is that low pressure can have a dozen different causes, ranging from a simple aerator clog you can fix in five minutes to a serious supply line issue that needs a professional. Here is how to figure out what you are dealing with.

This is the most important question to answer before anything else.

Low pressure at one fixture only — a single faucet, showerhead, or toilet — almost always points to a localized problem: a clogged aerator, a partially closed shutoff valve, or a failing fixture. These are usually easy and inexpensive to fix.

Low pressure throughout the whole house is a different story. That points to something upstream — your main supply line, your pressure regulator, your water meter, or even the municipal supply itself.

Start by checking every faucet in the house. That single piece of information will save you a lot of troubleshooting time.

The aerator is the small screen at the tip of your faucet. Over time, mineral deposits — especially in areas with hard water — build up and restrict flow. This is the most common cause of low pressure at a single fixture and the easiest to fix.

DIY fix: Unscrew the aerator, soak it in white vinegar for an hour, scrub with an old toothbrush, and reinstall. Same approach works for showerheads.

Every fixture has a shutoff valve underneath or behind it. If someone partially closed one during a repair and forgot to reopen it all the way, you will get reduced flow at that fixture. Check the valves under sinks and behind toilets — they should be fully open (turned counterclockwise as far as they go).

Your main shutoff valve — usually near the water meter or where the main line enters the house — can also cause whole-house pressure loss if it is not fully open.

Most homes have a pressure reducing valve (PRV) installed where the main line enters the house. Its job is to step down the high pressure from the municipal supply to a safe level for your home's pipes (typically 40–80 PSI).

When a PRV starts to fail, it can cause pressure to drop dramatically — or in some cases, spike dangerously high. PRVs typically last 10–15 years. If yours is older and you are experiencing whole-house pressure issues, it is a prime suspect.

A plumber can test your pressure with a gauge in minutes. If the PRV is the culprit, replacement is a straightforward job.

In older homes — especially those with galvanized steel pipes — mineral deposits build up on the inside walls of the pipe over decades, gradually narrowing the passage for water. Think of it like cholesterol in an artery.

This is a slow, progressive problem. You may not notice it happening until the pressure has dropped significantly. Unfortunately, there is no cleaning solution for this — the only real fix is repiping the affected sections with copper or PEX.

If water is escaping through a crack or pinhole leak before it reaches your fixtures, pressure drops. A slab leak — a leak in the supply lines running under your concrete foundation — is a common culprit in East Texas homes and can be surprisingly hard to detect because the water soaks into the ground rather than pooling visibly.

Signs of a hidden leak alongside low pressure:

• Water bill higher than normal with no change in usage
• Warm or damp spots on the floor
• The sound of running water when everything is turned off

If you suspect a leak, call a plumber. Slab leaks do not get better on their own.

Sometimes the problem is not in your house at all. If your neighbors are also experiencing low pressure, or if the issue came on suddenly, contact your water utility. They may have a main break, be doing maintenance, or have a pressure issue in your area.

• Is the low pressure at one fixture or the whole house?
• Have you checked that all shutoff valves are fully open?
• Is your home more than 20 years old with original pipes?
• Is your water bill higher than normal?

Two or more checked? Time to call a plumber for a proper pressure test.

A pressure test takes about 15 minutes and tells us exactly what your supply pressure is and where it is dropping. From there, we can pinpoint whether the issue is your PRV, your pipes, a leak, or something else entirely.

Back 2 Good Plumbing serves Trinity County and Deep East Texas. We will diagnose your pressure problem and give you a straight answer — no guesswork, no upselling.

Call us at 936-300-2437 or use our contact form to get scheduled. Low pressure is fixable — let us find out what is causing yours.