A fast drop in only one faucet means there's a problem with the faucet. Rapid low pressure affecting one area of the house may mean a corroded pipe issue. An abrupt water pressure drop affecting the whole house may mean a water main break (municipal water) or a well pump problem (well water).
If you experience a sudden decrease in pressure, give your utility company a call to see if there have been any issues that would impact your neighborhood. You can also check the valve at the water meter.
Check for a pressure-reducing valve (PRV) mounted on your water main. Most come set from the factory for 50 psi, but you can adjust them up or down by turning a screw on top. PRVs can also go bad after 10 to 20 years. So if yours is old, it might be time to replace it.
To return to full pressure only takes seconds. Flushing and recirculating takes minutes if you open all the taps, with the exception of tank water heaters.
Opening the main valve (Open/Turn-on)
Close all faucets except a tub or sink on the highest level of the home. Partially turn on valves slowly; extra slow for lever handles; stop after ½ revolution on wheel handle, ½ of a ¼ turn for lever handle; with water flowing, slowly turn off highest open faucet.
The house water shut off valve can easily affect water pressure if it is accidentally nudged towards the off position, thus restricting water flow and causing low pressure. The water shutoff valve is located outside the house at the water meter or near the PRV.
Water pressure regulator replacement: $250 to $1,000. Pipe section replacement: $500 to $4,000.
Typically, water pressure regulators cost about $50 to $100 on average1, though you could end up paying up to $2001 depending on the size of incoming water line.
The city could be flushing hydrants.
In any of these cases, the pressure loss will be temporary. But when the water does come back online, it will definitely kick up sediment, which can clog supply valves and faucet aerators. Be prepared to flush them if the pressure seems low when the water comes back on.
Normal water pressure range
In general, residential water pressure ranges between 45-80 psi (pounds per square inch). If your water pressure is under 40 psi, it's considered low. A psi between 20-30 is considered very low, and under the minimum water pressure required by most building codes.
However, when low water pressure originates from an issue specific to your home, such as a water pipe or your pressure regulator fails, plumbing repairs can correct the problem.
A water pressure booster can help many households. This booster adds to the existing plumbing system and accelerates water flow through the pipes, increasing pressure. If DIY solutions don't work, don't be afraid to call a professional for help.
Do All Homes Have a Water Pressure Regulator? No, and in some cases, you may not need one. Certain municipal supplies regulate their water pressure safely, but if that pressure runs above 80 psi, you'll want to protect your plumbing system by installing one.
Some of the first signs of a failing pressure regulator are a leaking water heater or commode. The water coming from a faucet may also exit with such force that splashing or water “hammering” may occur.
Once all your faucets are turned on, including the outside spigots, turn the water valve all the way on. Let the water run through all of your faucets for 10-15 minutes to make sure you are seeing a steady stream of water, or aren't hearing any noises coming from your piping anymore.
Warning: Turn the valve slowly to turn on the water to your home. Opening the valve too quickly can result in damage to the pipes in your home. Be sure to also clear any air from the water lines. You can do this by opening the hose-bib next to the master shutoff valve and running the water until the air is released.
It may be caused by debris such as dirt, sand, solidified oil and grease, food particles, or foreign objects. Pollutants can block pipes if they back up due to fractures in the water main. Mineral buildup clogs pipes over time and causes the water pressure to go down, as there's less space for water to travel through.
A quick and easy way to increase water pressure is to adjust the pressure-reducing valve, which can be found in your home, usually close to your water meter.
Find the spigot closest to your source of water. Make sure all the taps and other water uses are turned off in your house. Now turn on the spigot and see how long it takes to fill the bucket. Dividing the number 60 by the time to fill the bucket will give you the gallons per minute number.
Allison Strube, director of water utility for San Angelo, Texas, explained if the pressure in the system drops below 20 PSI, the system becomes vulnerable for bacteria from groundwater or dirt to seep into the pipe and affect the water supply.