Solving Low Water Pressure Problems

Low Water Pressure - Now here is a thing of beauty. It is my main shutoff valve with a system drain cock just above it. As you can see, it would be no problem to work on this aspect of my system. I'll never have to as I installed a ball valve for the main shut off.

DEAR TIM: All of the fixtures in our three year old home have had horrible water pressure since the day we moved in. If you have two garden hoses on the second floor toilet will not flush. Our builder has not done a thing to help us. Our next door neighbor's house was built the same year and has excellent water pressure. What in the world could be so different between our two homes? Is there a way to easily diagnose the problem? Shelly W., Spokane, WA

DEAR SHELLY: What a shame your builder is ignoring the problem. An abundant supply of water is one of the most basic essentials in a new home. There most certainly is a problem and the good news is that you will have pressure and volume equal to that of your neighbor's house in short order. Since you are both tied into the same water main and their pressure and volume is fantastic, it is not unreasonable to expect identical results.

There are several things that can cause a low pressure and volume problem. Some are easy to spot while others are hidden. The first thing I would look at are all of the shut off valves from the street into your home. You need to make sure these valves are in the full open position. Two critical valves to look at are the ones on either side of the water meter. If you have an outdoor meter that is in an underground pit, you may have to purchase a special socket wrench to open the meter box cover. Visit a plumbing supply house for one of these special five point sockets.

The shut off valves at a water meter usually have a long bar on top of the valve. This bar needs to be pointing towards the center of the water meter if the meter is centered between the two valves. Often this valve rotates just 90 degrees. To make sure it is in the full open position simply turn the valve to the off position and rotate it backwards 90 degrees until it is totally open. If you choose not to operate these valves, simply call your local water works and ask them to assist you. Frequently they will do this for no cost.

You are looking at my water meter. It is in a pit in the ground. There is very little room to work. Don't mess around here if you are a rookie!

Next, check the indoor main water shut off valve. See if it is also in the full open position. Believe it or not, someone may have partially closed it years ago and never fully opened it. Stranger things have happened. If this valve is an old fashioned gate valve or one with a traditional washer and rising stem, a malfunction within the valve can cause the valve to appear to be in the full open position and yet the valve could be partially closed. This is why I prefer to use full sized ball valves that open to the full diameter of the pipe size that they are connected to. If you do not have a ball valve at the main shut off, I urge you to install one.

If all of the valves are fully open and the water pressure is still low at all locations within the house, this indicates that there is a restriction in the line. The buried portion of the water line leading to your home from the street could be crushed or crimped in one or more locations. The plumber that installed the buried line could have accidentally dropped a large rock on the line while backfilling the trench.

Although remote, there could be a large stone or pebble blocking the water line or one of the valves. The only way to determine this is to break open the water line at the water meter and see if you have excellent volume and pressure at that location. If so, you know the trouble lies between that point and your home.

The problem could also be the actual water meter. It may have an obstruction within it. This can be verified by taking the water meter out of its saddle and installing a bypass pipe. If you have excellent pressure and volume you know that the meter was the offender. But do not attempt to perform this test yourself. Virtually all meters are sealed to prevent tampering. You must have your local water works personnel perform this bypass test. Some local plumbing codes may also restrict you from working on the water lines. Be sure to consult your local plumbing inspector to find out what you can and can not do yourself.