What Causes Low Water Pressure?

Person washing hands with text: What causes low water pressure
You may not realize how much you rely on water to accomplish all sorts of tasks until you run into a problem with your water supply. In the worst cases, some issues can leave you without access to water at all for a time. Even when your water is working, you may still experience issues from low water pressure. Low water pressure is when the water that comes out of plumbing fixtures, like faucets or shower heads, weakly dribbles out rather than sprays out at the speed and volume it typically does.

When your water pressure is low, it can significantly affect the quality of living in your home. Everything from showering and washing dishes to doing laundry and more will become longer, more frustrating tasks when your water pressure is diminished. To fix the issue, you need to understand the cause. In this post, we will look at several possible causes for a loss of water pressure in your home and what you can do to address the problem.

Understanding Water Pressure

If your water comes from a municipal water provider, it is pumped from a natural water source to a treatment facility, which moves to pressure tanks at higher altitudes. A common example of this is a water tower. Gravity creates pressure naturally, so when your water comes to you, it is already pressurized. In some cases, booster stations help to maintain the pressure throughout the water lines in a city. If your water comes from a private well, then your water is pressurized through a tank that maintains a range of pressure.

Residential water pressure should ideally be in the range of 45 to 55 pounds per square inch (psi), but it typically ranges from 45 to 80 psi. A psi reading under 40 is considered low and a reading under 30 is definitely too low.

Quick Start Guide for Diagnosing Low Water Pressure

Before we discuss several potential causes for low water pressure in detail, we will take a moment to give you a quick overview to help you get started. Here are several reasons why you may experience a loss of water pressure in your home:

Too much demand on water: In some homes, having multiple plumbing fixtures on at once can place too high of a demand on the water supply for proper water pressure to be maintained in every fixture. With a little coordination, you can usually avoid this issue.
Faulty fixtures: Fixtures themselves, such as shower heads or faucets, can become faulty or clogged over time. In some cases, simply cleaning out the screen or aerator is enough to fix the issue, but at other times, an entire fixture may need to be replaced.
Broken pressure regulator: Water pressure regulators are designed to help stabilize water pressure in your home, keeping it within a certain range. When these regulators go bad, your water pressure can either become too high or too low.
Closed valves: Your home's water supply can be shut off by two different valves. You can check both of these valves on your own. If either of these valves is not fully open, it can affect the water pressure throughout your home.
Clogged pipes: If pipes become clogged, these blockages can disrupt water flow through your pipes. With the flow disrupted, water pressure will also go down. Pipes need to be cleaned out or replaced to address the issue.
Corroded plumbing: Clogs can be fixed by cleaning out or replacing small piping sections. Over time, though, your entire piping system can become corroded, which will negatively affect your water pressure.
Plumbing leaks: Leaking pipes can cause water to redirect its path and end up in an unwanted area, such as a basement or ceiling. While temporary fixes for this issue are possible, a permanent fix should be done by a professional.

Keep reading for more detailed explanations of these issues and how to fix them. Remember that, in most cases, you will make your life much easier and avoid further complications by calling in a professional to address the problem.

How Many Locations in Your Home Have Low Water Pressure?

When you are investigating an issue of low water pressure in your home, the first thing to note is the scope of the problem. In other words, you need to know how many plumbing fixtures are experiencing decreased water pressure. You may find the issue only affects one fixture, all fixtures in a certain room or every fixture throughout your house.

This is important information since it can help you trace the issue. If only one fixture is experiencing low water pressure, then it may just need an easy fix related to that fixture alone. In other cases where water pressure is low throughout the house, it may indicate a more serious issue in your plumbing.

Go through the interior of your home and around the exterior to check each plumbing fixture, including:

Dishwasher
Sink faucets
Toilet
Shower
Bathtub
Washing machine
Outdoor faucet
Hose hookups

As you go to each fixture, turn it on and test both the hot and cold temperatures. Is the water pressure only low on the hot setting? Is it only on the cold setting or is it low for both? If you find that water pressure is only low when a fixture is on the hot water setting, for instance, then the issue could lie with your water heater.

What Causes Low Water Pressure?

Low water pressure can be frustrating for task efficiency or your water bill. Learn more about the top seven primary causes of low water pressure.

1. Running Multiple Water Fixtures

Often, when you experience a decrease in water pressure, it is because two different plumbing fixtures are on at the same time. For example, you might turn your shower on while your dishwasher is running and notice that the water from the shower head is not as pressurized as usual. Or, you may see that your washer is taking longer to fill up than normal while someone is running the hose outside.

This occurs because your water supply only has so much to offer at any given time. When you need a water flow in two or more places at once, the water has to divide rather than all going to one place, reducing the pressure. If dividing your water flow is causing low water pressure, then your water pressure should go back to normal when there is not such a high demand on your water flow.

In the case of a weak shower, wait until the dishwasher is finished running and try turning on the shower head again. In the case of the washer, turn off the hose outside and see if the washer fills up faster. If everything goes back to normal when you only use one plumbing fixture at a time, you can enjoy good water pressure. However, you should still keep an eye on your water pressure to see if it eventually drops too low, as this could indicate a problem that needs to be fixed.

2. Outdated Fixtures

In some cases, low water pressure can be caused by fixtures that have become faulty over time. A build-up of mineral deposits, including rust, limestone or sediment, can obstruct the fixture and prevent water from flowing freely. This not only diminishes water pressure but can also impact the quality of the water that comes out. This may be the case if you notice the low water pressure in just one or two fixtures.

Test all your fixtures one at a time by turning them on and observing the water's pressure. Check to make sure any screens or aerators on your faucets are clean and unobstructed. If a screen or aerator is clogged, you may only need to replace that piece to fix the issue. If this piece is clear, it may be that the fixture itself is clogged. If so, you can clean it out or replace it on your own.

If you replace your whole fixture, purchase a new one that will fit correctly. For faucets, after taking your old one out, measure the distance between the two outer holes. A distance of six inches or more means you need a wide-spread faucet. This faucet requires you to manually connect the two valves to the mixing tee.

A distance of just four inches means you need a mini wide-spread or a center-spread faucet. This faucet type is already combined into a single unit encompassing all parts. You can tell the difference between a mini wide-spread and a center-spread faucet just by looking at the top of your sink. A mini wide-spread faucet looks like three separate pieces, while a center-spread looks like all one piece. When you work on replacing a fixture, be sure to shut off the water supply.

3. Pressure Regulators

In some cases, a faulty pressure regulator may cause low water pressure. It can also cause water pressure to be too high. If you find little to no middle ground between low and high water pressure when turning on a faucet in your house, then this is a sign you are likely dealing with a failing water pressure regulator.

Not all homes are equipped with a pressure regulator, but if yours is, you will probably find this bell-shaped device below your home's front hose connection. Once the manufacturer sets the pressure regulator — typically to around 45 to 60 psi — it should not need adjusting. However, turning the screw at its tip can adjust your pressure regulator. Gradually turn the screw clockwise to tighten it or counterclockwise to loosen it. Tightening the screw should cause your water pressure to increase, and loosening the screw should cause your water pressure to decrease.

If your water pressure was well-regulated before but is now too high, too low or both, then your pressure regulator may need to be fixed or replaced rather than adjusted. Pressure regulators can go bad, and when this happens, you should not try to fix or replace it yourself, as this can make problems worse. In this case, you are better off relying on a licensed plumber to evaluate the situation and either repair your current pressure regulator or install a new one.

4. Water Valves

Two main shut-off valves control the water flow in your home — one on or in your home and one at the meter. If one of these valves is partially or fully turned off for some reason, it can cause your water pressure to decrease considerably. This might happen when the water is temporarily shut off and then turned back on again — a valve could accidentally be left partially closed rather than opened back up all the way. If you think a closed or partially closed valve may be the cause for your low water pressure, check both main valves to make sure they are fully open.

To check the water meter valve, go to your water meter, either inside or outside your home, and look inside the box. Many water utility companies install water meters near the edge of your property near the street. If you live in an area that experiences harsh winters, your meter may be located indoors, probably in the basement, for protection. Sometimes, only city employees have full access to your meter, though you can still observe whether the valve is completely in the on or open position.

To check the home valve, look near your home's hose bib. Though this main shut-off is typically located on the exterior of your home, it can sometimes be in a utility room or basement. Shut-off valves are usually either ball or gate valves. Ball valves have a clear open and closed position, whereas gate valves need to be turned like a screw and may require several turns to fully open or close the water flow. If a valve appears to be broken, contact a professional who can see if the valve needs to be replaced.

5. Clogged Water Pipes

Another potential cause of low water pressure is clogged pipes. Clogged pipes may be the issue if water sprays out at a normal pressure when you first turn on a faucet, but then it immediately begins to flow with noticeably less pressure. Pipes can become clogged over time as mineral deposits, rust or other debris build up on the insides of the pipes and restrict the flow of water. This is especially an issue with galvanized pipes. For this reason, galvanized steel is no longer the material of choice for new pipes. However, it used to be a very common material and is still found in many homes.

If you are not sure what the pipes in your home are made out of, find a pipe and use a nickel to scratch the surface so you can see the original color of the material. If the pipe's exterior looks like a penny, it is most likely made of copper, a very common piping material. Plastic pipes are also fairly common. These are usually black and are easy to identify by the visible clamps. The surface of galvanized steel pipes will look steel-gray in color.

While you can see what your pipes are made out of, this is where your investigation should end. Unlike other problems that can cause decreased water pressure, you cannot check this one yourself. If you suspect your pipes may be clogged, call a licensed plumber to take a look and determine whether the pipes need to be cleaned or replaced. If so, the plumber should take care of it. You should not attempt to work on pipes on your own. Attempting to clean out clogged pipes when you do not have the necessary expertise is not only difficult, but it can also be dangerous — for instance, you could inadvertently contaminate your drinking water supply.

6. Corroded Plumbing

It's one thing if you only have a section of piping that needs to be unclogged or replaced, but in some situations, a home's entire piping system can become corroded and may need to be completely replaced. Galvanized steel pipes have an average life span of 20 to 50 years. Materials like brass, copper and iron can last much longer, but even these pipes will most likely need to be replaced somewhere between 40 and 100 years. If you live in an older house, your plumbing may have been there for many decades and has become severely corroded.

Replacing all the plumbing in your house is a large undertaking and is costly, but the results are worth the effort. When putting new plumbing in, you can choose a durable material so you will not have to worry about replacing the piping again in your lifetime. Of course, this is a job for the professionals. Make sure you hire a licensed plumber to re-pipe your home.

Another thing to check is whether you need to enlarge branch lines. If you have added any new plumbing fixtures, the old branch lines may be too small. So, even though corrosion is not an issue in this case, you could still experience the same effect on your water pressure. The narrow interior of the line restricts the amount of water flowing through.

7. Plumbing Leaks

Similar to running multiple water fixtures, a plumbing leak can weaken water pressure. A leak prevents the water in your plumbing system from getting where it should, diverting the path and resulting in a restricted flow. If you have easy access to your pipes, look around to see if you spot any pooling or wet surfaces. If you can figure out which line is leaking, try this temporary fix until a plumber can fully remedy the issue.

First, you will want to turn off your water supply so you don't lose any more water and the pipe can dry. Wrap a rubber patch around the crack or corroded area and fasten it with electrical tape and a pipe repair clamp.

While this won't hold in the water for good, it can drastically change your water pressure and prevent further damage for a time. However, you will want a professional to come in as soon as possible. Dealing with a long-term leaky pipe can damage your foundations as well as contaminate your drinking water.

Consult a Professional

Many of the issues discussed above and more should be fixed by a professional. When it comes to plumbing, you do not want to neglect a problem or make the matter worse by trying to fix it yourself. When you encounter plumbing problems of any kind or when you want to check on your plumbing to ensure it is well-maintained, call Mr. Rooter Plumbing of Greater Syracuse.

We offer comprehensive residential, commercial and emergency plumbing services to take care of any issues you experience, including those that reduce water pressure in your home. When you call one of our plumbers in to take care of a problem, you can also take advantage of a complimentary plumbing checkup to diagnose any other potential problems with your plumbing.

Our service is unmatched within the plumbing industry. We understand that dealing with plumbing problems can be stressful, but we can eliminate the stress. We will schedule service as quickly as possible and provide you with a flat-rate upfront so you can rest easy that, no matter how long the job takes to complete, your cost will not change. Our plumbers' priority is getting the job done well, whatever it takes. You can also expect our plumbers to be courteous and treat your home with great care.