The short answer is low water pressure in your home arises due to a number of causes. Some include a shut or blocked water meter valve, mineral buildup clogs pipes, corroded pipes, or even a crack in the main city supply pipe to your home.
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).
Open your main water valve.
Your house has a main water valve, usually located near the meter; the valve controls the flow of water into your home's pipes. Find the valve and check to see if it's completely open. Opening a half-shut valve is one of the quickest ways for increasing home water pressure.
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.
If your valves are open all the way, and you're still experiencing slow water flow, the cause might be a clog. the water comes out. It has a screen and, over time, sediment gets caught in it, which impedes water flow. Remove the aerator and clean it thoroughly.
If there's an accumulation of sediments in your hot water tank, it can lower your water pressure. The presence of kinks in the flexible water pipes used in water heaters can result in low water pressure. If the shut-off valve isn't fully open, water pressure can drop.
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.
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.
Pressure-Reducing Valve
Look on the main supply pipe near your water meter for a conical valve that has a bolt sticking out of the cone. To raise pressure, turn the bolt clockwise after loosening its locknut.
Water pressure regulator replacement: $250 to $1,000. Pipe section replacement: $500 to $4,000.
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.
How long will a Water Pressure Reducing Valve last? The life expectancy of a water pressure regulator is most commonly in the range of 10 to 15 years. However, you may see a regulator malfunction at three years and one still properly functioning at 20 years old if regularly maintained.
When a pressure tank becomes water-logged, the pressure inside of it fluctuates frequently, which causes the well pump to cycle on and off. The well pump cycling leads to water pressure going from low to regular in your plumbing fixtures. That's when you would notice your shower stream die down and then come back.
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.
If the PRV is improperly adjusted, or has failed, it can result in a pressure loss or even no water downstream.
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.
These air bubbles usually find their way to the highest points in your plumbing system, lower water pressure, and inhibit the flow of water through the pipes. Air in the water piping system can cause rust and corrosion. Rusted pipes weaken, and the rust can drop sediment into your water.
On average, a water pressure regulator can last from four to 12 years in a healthy plumbing system. However, most manufacturers recommended replacing water pressure regulators about once every five years to limit any potential damage high water pressure could have on the plumbing infrastructure.
PRV Age. The spring in the diaphragm can lose tension over time. Make sure you replace your PRV every 4-5 years to avoid problems due to age.
The price of pressure reducing valves starts at around $50. You can expect to pay around $350 for a professional plumber to install a new pressure reducing valve.
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.