When it comes to water pressure, what one person thinks is adequate might come across as a trickle to another. Because opinions vary widely, it is important to be able to make a determination of the adequacy of water pressure in some definitive way. That is especially true for a working home inspector. If a client asks why the inspector did not comment on high or low water pressure, then having a normal water pressure reading documented on the report is a good idea.
Water pressure gauges are easy to use practical tools and, certainly, not out of the reach of the homeowner in either cost or the expertise required to operate them correctly. In fact, these gauges can be purchased at any good hardware store for about $10.00. Once you have the device, you might wonder what readings you are looking for? Well, normal pressure is described as being between 40 and 80 PSI (pounds per square inch). The easiest place to check that reading is to screw the gauge on at an outside faucet. Beware, there can be a potential snag doing that: Not often, but sometimes, the hosebibb or faucet is plumbed in before a pressure reducer is put in the system and, in that case, there will be a high reading on the gauge. For this reason, when a hosebibb gives a high reading, a person should try to get another reading, such as attaching the gauge to the faucet the washing machine connects to. The washing machine faucet is usually inside the home, or so we hope, and has the same threads as the pressure gauge. If the reading is still high, then the problem is confirmed since the washing machine is one of the appliances we are trying to protect from damage caused by high water pressure.
As an aside, it is my opinion, having inspected many homes and then checked the water flow, that any reading under 50 PSI is suspect and the people who are going to live in the house ought to see for themselves if they like the water pressure. If a person buying a house does not have a pressure gauge, or wonders if he or she will be satisfied with the water pressure, I suggest the good old- fashioned multi-flow test. It is simple enough. Get the dishwasher or washing machine running. Then turn on a sink or two and go to a bathroom and try the shower, the sink, etc. Do this on each floor, with other fixtures running. You can get a pretty good idea of the adequacy of the water pressure and how it will affect you.
As far as solutions to a pressure issue: If the pressure is too high, a pressure reducer will probably be installed by a plumber. If, on the other hand, the water pressure is too low then that will be more complicated. The cause can range from bad pressure at the source, to rusted pipes and a number of other issues.