Some Plumbing Facts…

Plumbing has come a long way since the days of outhouses and hand pumps. We rely on the convenience of today’s plumbing so much that we take it’s reliability for granted.

Unfortunately, many home owners don’t know the basics of their plumbing system. When a major problem occurs, they are left at the mercy of a contractor; trusting his estimate of the damage and repairs. Although most contractors are honest, it helps to know as much as possible when hiring a plumber.

This information is intended as a general home owner’s guide to the basics of residential plumbing.

water flow

Water Supply

Your potable (drinking) water is supplied by either a municipality, a utility company, or a well. If you have a well, water is pumped from the well by a motorized pump into a pressure tank, and then into the supply system. When demand in the house causes pressure in the tank to drop, the pump turns on, and water is drawn out of the well to refill the tank. The pump shuts off automatically when the pressure is  re-established.

Water flows into most homes through a water service line at a pressure of 20 to 80 pounds per square inch (psi). Typical psi is between 25 and 50. A main shut-off valve is usually installed on the line near where it enters the building. You should know where the valve is located because you may need to shut off your water supply if you have a leak or are having plumbing work done.


Once inside the house, the pipe may connect to the water softener (if you have one), and then to the water heater. From the water heater, the piping branches out horizontally and vertically to fixtures such as tubs, toilets, showers, and sinks.

Horizontal pipes may be installed on a slight decline so that in case of power failures or major repairs, the entire system can be drained through a valve at its lowest point.

Supply pipes are sometimes designed with air chambers which act as “shock absorbers” when faucets are rapidly turned off. Without these, the system could develop ruptures from the pressure created by water flow being abruptly stopped. Some- times these chambers become filled with water, and you will hear banging in the pipes known as “water hammer”. If the banging persists, the air chambers can be re-established by a plumber or a handy home owner with the aid of a repair manual.

Water Heaters

Most homes have their water heated by electric, gas, or oil- fired heaters. Tanks normally range in size from 30 to 82 gallons. Modern tanks are covered with a thin layer of enamel to prevent corrosion. Insulation is placed between the tank and the outer metal jacket to minimize heat loss and condensation.

To guard against excessive temperature or pressure, every water heater must have a temperature/pressure relief valve that automatically releases water when the temperature or pressure in the tank reaches its limit.

The temperature setting should be kept as low as is safe to conserve energy and prolong tank life. Water should be at least 110 degrees Fahrenheit to kill microbes; and no more than 130 to 140 degrees Fahrenheit to prevent  scalding.

Inside some tanks, replaceable magnesium rods are sus- pended in the water to attract corrosive electrolytes that would otherwise consume the tank walls. These rods can be checked and replaced periodically; however, as a practical matter, this is rarely done.

Water Softeners

In some geographic areas, water contains excessive amounts of calcium and magnesium, and is known as “hard water”. Hard water leaves rings around bathroom fixtures and can build up mineral deposits in water heaters and pipes. Water softeners remove these minerals and replace them with sodium. The sodium in a properly operating system is minimal.

However, if you are concerned with excess sodium in your diet, the softener can be connected to the water heater only, so the drinking water is not treated. Consider having the water analyzed to determine if there is reason for concern!


To most people, the workings of the toilet seem quite complicated but they’re really quite simple! When the tank handle is pushed or lifted, a connecting rod raises a rubber stopper from a valve at the bottom of the tank. Water from the tank rushes into the bowl and the tank’s float ball drops with the water level. As water fills the bowl, gravity and a siphoning action draw the contents of the bowl through the trap and into the drainage system.

After the tank water is released, the rubber stopper drops down to seal the valve at the bottom of the tank. Water from the supply line flows through a ballcock valve to refill the bowl, and then the tank. The float ball rises with the water on an arm that shuts off the ballcock valve when the water in the tank reaches the proper level.

If your plumbing system is operating properly, water pressure should be consistent. For example, water coming out of an upstairs sink should not be significantly reduced when the bathtub is running simultaneously. Sometimes, even if water pressure is in the normal range, water flow can be diminished if mineral deposits have built up on the inside surface of pipes, or in faucet nozzle screens. These screens should be periodically  cleaned.

Most interior residential water supply systems use one or more of the following materials for piping: galvanized iron, copper, brass, lead or plastic. If your piping is lead, you may want to have the water tested to determine if the lead is contaminating your water supply.

Regardless of the material used, all piping systems must be adequately supported by, or attached to, the studs or joists with compatible hangers, clamps or other approved devices.

plumbing pipes
water softener