Common Causes of Low Water Pressure

What Is Low Water Pressure?

Water pressure is the force that pushes water through your pipes and fixtures. In most homes, it should fall between 40 and 60 PSI (pounds per square inch). If it drops below 30 PSI, most homeowners will notice performance issues.

Common Signs of Low Water Pressure:

• Weak flow from faucets or showerheads
• Inconsistent pressure between fixtures
• Washing machines or dishwashers taking longer to fill
• Hissing, gurgling, or banging pipes when taps are turned on

While occasional dips in pressure might not be serious, persistent low water pressure can signal bigger plumbing issues—like clogs, leaks, or aging pipes. If left unresolved, these problems can affect water quality, appliance efficiency, and even lead to water damage.

The good news? Most causes can be identified and fixed with the right approach. Let’s look at what could be behind the drop in pressure and how 1st Call Plumbing & AC can help restore proper flow to your home.

What Causes Low Water Pressure? 8 Common Problems We See in San Antonio Homes

Even if your fixtures are in great shape, your water pressure problems could be coming from deeper within your plumbing system. 

Here are the most common culprits we see in San Antonio homes:

Pipe Clogs

Over time, minerals, rust, sediment, and even grease can build up inside your pipes, especially in hard water areas like San Antonio. As these deposits accumulate, they narrow the pipe’s interior and restrict water flow.

This is common in older homes with galvanized steel or copper pipes, where buildup has had years to form. But even newer homes can develop clogs from construction debris, soil shifts, or failing water heaters.

What to look for: Low pressure at one or more fixtures, sputtering water, gurgling or whistling sounds, and discolored water that may indicate rust or sediment.

What to do: Minor clogs in faucets or shower heads can often be cleared with vinegar. If multiple fixtures are affected, the blockage is likely deeper. Call 1st Call Plumbing & AC for professional pipe cleaning or descaling to restore proper flow.

Corroded Pipes

As plumbing systems age, corrosion becomes a common issue, especially in homes built before the 1980s that used galvanized steel or cast iron pipes. These materials are prone to rusting from the inside out, which gradually restricts water flow. Even if the pipes look fine on the outside, corrosion inside can significantly reduce pressure.

What to look for: A steady decline in water pressure, rusty or discolored water (especially after the water sits unused), sediment in the water, or visibly aged or patched pipes.

What to do: Corrosion can’t be reversed. In many cases, repiping is the best long-term fix. 1st Call Plumbing & AC offers full and partial repipe services using durable, corrosion-resistant materials like PEX or copper to restore reliable pressure.

Leaking Pipes

Leaks don’t just waste water, they divert it away from your fixtures, which reduces pressure. Many leaks are hidden behind walls, under floors, or even underground, so they’re easy to miss until damage appears. Even a small leak can cause noticeable pressure drops and, over time, lead to mold, warped flooring, or structural damage.

What to look for: A sudden drop in pressure, water stains on ceilings or walls, musty odors, visible mold, or unexplained spikes in your water bill.

What to do: If you suspect a leak, don’t wait. Our team provides emergency plumbing repair with advanced leak detection tools to locate and fix the issue quickly.

Malfunctioning Pressure Regulator

Some homes have a pressure-reducing valve (PRV) that controls the pressure of incoming water. If it fails, you may notice sudden swings in pressure, either too high or too low, throughout the house.

What to look for: Sudden pressure changes, banging noises in your pipes (also known as water hammer), inconsistent flow from faucets, or sputtering followed by normal flow.

What to do: A faulty PRV should be inspected and replaced by a licensed plumber. 1st Call Plumbing & AC can test and replace it quickly to restore consistent water pressure.

Municipal Supply Issues

Not all pressure problems come from inside your home. Cities occasionally reduce water pressure during maintenance, after a main line break, or during high-demand periods. Sometimes, even hydrant flushing or nearby construction can cause temporary pressure dips.

What to look for: Low pressure in every fixture, including outdoor taps, and neighbors experiencing the same issue, without any visible plumbing problems in your home.

What to do: Check with your local water provider or ask neighbors if they’re having the same experience. If it’s just your home, we can inspect your service line and plumbing system for internal issues.

Partially Closed Valves

Your home’s water flow depends on two key valves: the main shut-off valve and the water meter valve. If either one is partially closed your entire home may experience low pressure.

What to look for: Uniform low pressure throughout the house, recent plumbing work or water shut-offs, or difficulty turning the valve.

What to do: Ensure the main valve is fully open. If you’re unsure or can’t access it safely, our team can inspect your system and make any necessary adjustments.

Aging Fixtures or Clogged Aerators

Sometimes, low pressure is limited to a single faucet or showerhead. Over time, aerators and fixtures can clog with sediment, especially in areas with hard water. This restricts flow at the point of use, even if the pressure elsewhere in your home is normal.

What to look for: One or two fixtures have weak flow, uneven spray patterns, or visible mineral buildup on the nozzle.

What to do: Clean the aerators by soaking them in vinegar to dissolve buildup. If that doesn’t help, replacing the fixture is a quick fix. If multiple fixtures are affected, it may indicate a deeper plumbing issue.

High Water Usage in the Home

If your household uses a lot of water at once, like running the dishwasher, washing machine, and multiple showers at the same time, it can temporarily lower pressure. This is especially common in homes with older plumbing or smaller pipes that can’t handle high demand.

What to look for: Pressure drops during peak usage times, slower flow when multiple fixtures are in use, or fluctuations throughout the day.

What to do: Try staggering appliance use or shower times. For long-term relief, we can evaluate your system and recommend upgrades like pressure booster pumps or wider-diameter pipes to better support your household’s water needs.

Troubleshooting Low Water Pressure at Home

Before jumping to conclusions or scheduling a plumbing appointment, there are a few simple checks you can do on your own. These DIY steps can help narrow down the source of your low water pressure and determine whether the issue is isolated, widespread, or urgent.

Here’s what we recommend:

• Test a few faucets and showerheads around your home. If it’s just one fixture, it’s likely a clogged aerator. If multiple spots are affected, the issue may be deeper in your plumbing.
• Ask your neighbors if they’re experiencing similar water pressure issues. If they are, it may be a city supply problem like maintenance or a main line break. If not, the issue is likely inside your home.
• Look for signs of leaks by checking for wet spots, stains, musty smells, or hissing sounds near plumbing fixtures. Even small hidden leaks can reduce water pressure and lead to costly damage if left unchecked.
• You can also test your water pressure with a gauge on an outdoor faucet. A healthy range is between 40 and 60 PSI. If it reads below 40, there may be a problem. If it’s under 30, it’s best to call a plumber.
• Review your latest water bill. A sudden spike in usage often points to a hidden leak, even if there are no visible signs.

Still unsure what’s causing the issue? That’s where our team at 1st Call Plumbing & AC comes in.

When to Call a Professional for Low Water Pressure

Low water pressure isn’t just a daily inconvenience, it can be a sign of something much bigger. Issues like corroded pipes, underground leaks, faulty pressure regulators, or outdated plumbing systems can all hide behind that weak water flow. Left unchecked, these problems may lead to water damage, mold growth, or costly repairs down the road.

That’s why it’s important to act early—especially when:

• Your own DIY troubleshooting hasn’t solved the issue
• Water pressure drops suddenly or without warning
• You notice signs of corrosion, leaking, or pipe damage
• You want expert insight and peace of mind with a full system evaluation

At 1st Call Plumbing & AC, we specialize in identifying and fixing pressure problems at the source. Whether it’s a simple fix or a major system upgrade, we bring almost 40 years of trusted experience to every job. We proudly serve San Antonio, Boerne, New Braunfels, Spring Branch, and surrounding communities with fast, reliable plumbing repair and replacement services.

Why Choose 1st Call Plumbing & AC?

Homeowners across San Antonio, New Braunfels, Boerne, and nearby areas choose 1st Call Plumbing & AC because we treat every home like our own. With almost 40 years of trusted, high-quality service, we’ve earned a reputation for honesty and lasting results.

Here’s what sets us apart:

✅ Licensed Plumbers: We’re licensed by the Texas Department of Licensing and Regulation and the Texas State Board of Plumbing Examiners, so you know you’re getting service that meets the highest professional standards.

✅ Free Estimates, No Trip Charges: We believe in transparency. Whether you’re scheduling a plumbing repair or replacement, you’ll receive a free, no-obligation estimate, with no trip charge.

✅ Emergency & Weekend Availability: We know plumbing problems don’t follow a 9-to-5 schedule. That’s why we’re available 7 days a week from 7:00 AM to 7:00 PM to ensure your comfort isn’t compromised.

✅ 4.9-Star Customer Rating: With more than 1900 verified reviews, we’ve earned a reputation for reliability, professionalism, and honest service. Just check out what your San Antonio neighbors are saying!

✅ One-Stop HVAC & Plumbing: Got an issue that involves more than just your air conditioning system? We handle full-service plumbing too—from gas line repairs to water heaters and leak detection.

We don’t just fix plumbing problems, we provide long-term solutions designed to keep your home comfortable, efficient, and protected for years to come.

Final Word on Fixing Low Water Pressure

At 1st Call Plumbing & AC, we believe in solving problems at the source. Whether you need a minor repair, updated plumbing, or just expert advice, our licensed technicians are here to help, honestly, promptly, and professionally.

📞 Request a Free Estimate Today

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