Getting to Know Your System

With so many pipes and fittings running unseen inside walls and floors, a plumbing system can seem complicated and mysterious. But plumbing is actually a straightforward matter of distributing incoming water to where it’s wanted and facilitating the outflow of waste. Here’s an overview of how household plumbing works.

Supply, drain, and vent systems - The supply system brings water into your house, divides it into hot and cold water lines, and distributes it to various fixtures (sinks, toilets, showers, tubs) and appliances (washing machines, dishwashers, water heaters, heating system boilers). The drain system carries water away from the fixtures and appliances and out of the house. The vent system supplies air to the drain pipes so waste flows out freely. Because drains and vents use the same types of pipes and are tied together, they often are referred to as the drain-waste-vent system, or DWV.

Where Your Responsibility Ends - The water meter is the continental divide when it comes to assigning responsibility for plumbing repairs. Most often, the water meter and pipes leading away from the house are the responsibility of the water company. Anything on the house side of the meter is your responsibility. However, if you will be adding new fixtures (not just replacing old ones), you may be required to have a larger water main coming into the house. If so, you’ll have to pay for it. Check when you get your permit.

Locating the water meter and main shutoffs - The first step toward gaining mastery over your house’s plumbing system is to locate the water meter and, more important, the main shutoff. Look for the place where water first enters your house. Usually, you’ll find a pipe an inch or so thick, called a water main, coming up through the floor in your basement or first floor. If you have metered water, the pipe will enter and exit a round gauge, the water meter. This has either a digital readout that looks like a car’s odometer or a series of five or six dials. The meter tells how much water passes into the house. If you have a well, or if your bill does not change no matter how much water you use, you don’t have a meter.

Near the place where the water main enters your house, look for one or two valves that you can turn on and off by hand. This is the main shutoff for the house. You may have an additional shutoff outside the house, buried in a cavity sometimes called a “buffalo box.” To find it, look for a round metal cover in the ground near the street or the edge of your property. It may be overgrown with grass. Pry it up and look inside with a flashlight. There may be a valve that you can turn by hand, or you may need a special long-handled “key.” Older homes in warm weather locations sometimes have an exposed valve just outside the house. If you have an older home, don’t depend entirely on the inside shutoff; it can break, leak, or stop shutting off completely. If you’ll have to shut down the system often during a project, learn where your outside shutoff is and use it to shut off the water.

Caution! Always Be Prepared to Shut Off the Water - In case of a burst pipe or other emergency, be ready to shut off the main water supply quickly. Let members of your family know where the main shutoff is. Clear away boxes and furniture so it is easy to get at. If it takes a special tool to shut off your water, keep it handy.

The New and the Old - In the old days, plumbers installed cast-iron drain lines. They had to pack each joint with tarred oakum, then pour in molten lead—a practice dating from the time of the Romans. For supply lines and smaller drain lines, they used galvanized pipe, which is strong but can rust and corrode over time. Plastic drain lines and copper supply lines are superior to the old materials. They last much longer and are easier to work with. However, it took many years for different localities’ codes to make the switch to modern materials. In some places, for instance, cast-iron was required by code well into the 1980s. Even to this day, some municipalities require that supply lines be made with galvanized pipe. If you have old pipe, there’s no need to rip it out. Many products are available that make it easy to connect the new to the old. These products often use gaskets that can remain leakproof for many decades.

Supply System

Water enters your house lr r through a pipe that connects either to a municipal water line or a private well. If your bill changes according to how much water you use, your water flows through a water meter. Near the meter you will find one or two main shutoffs. From there water travels to the water heater. Water from a private well goes to a pressure tank before going to the heater. From the water heater, a pair of water lines—one hot and one cold—branch out through the house to serve the various fixtures (toilets, tubs, sinks, showers) and water-using appliances (dishwashers, washing machines, heating system boilers).

These supply lines are always under pressure; if they are opened or a break occurs, water will shoot out and not stop until it is shut off in some way. That is why modern homes have stop (or shutoff) valves for every fixture and appliance. If your home is not equipped with them, plan to install them. They’ll make maintenance and repairs more convenient and will more than pay for themselves should you face a serious break. Older homes have plumbing systems that use galvanized pipe, which will corrode over time, leading to low pressure and leaks. Newer homes use copper and plastic supply lines, which last much longer.

Drain System

Drain pipes use gravity to rid the house of liquid and solid waste. This system also guards against foul-smelling and potentially harmful gases entering the house from the municipal drain system or the septic field. All fixtures except the toilet empty into a trap (toilets have built-in traps). A trap is a curved section of drain pipe that holds enough standing water to make an airtight seal that prevents sewer gases from backing up and leaking into the home. Each time a fixture is used, the old water in the trap is forced down the line and replaced with new water.

After leaving the trap, drain water moves in pipes sloped at no less than 1/4 inch per foot toward a waste stack (also called a soil pipe), a large, vertical pipe that carries water below the floor. There it takes a bend and proceeds out to a municipal sewer line or a private septic system. A clean-out is a place where you can insert an auger to clear the line. Traps serve the same function. Drain pipes come in 1 /1/4-inch pipe for a bathroom sink, 1 1/2-inch for kitchen sinks and bathtubs, and 3- or 4-inch for toilets. The stack is usually a 4-inch pipe. Older homes use cast-iron pipe for the stacks and galvanized pipe for the other drain lines. New homes use plastic, and occasionally copper, for stacks and drains.

Vent System

To flow freely, drain pipes need air. Without air, water will glug down a drain like soda pop from a bottle. A plumbing vent plays the same role as that little second opening in a gasoline can. With the stopper closed, gas pours out slowly. But once the stopper is opened, the air entering the can equalizes the pressure and allows the liquid to flow freely.

Also the air supplied by a vent prevents siphoning action, which might otherwise pull water up out of traps and toilets and allow sewage gases to escape into the house. Instead vents carry the gases through your roof. Sewer gas, composed largely of methane, is not only smelly, it is harmful and dangerous. Install a top quality venting system, even if it means a lot of work. A main vent is an extension of the waste stack and reaches upward through the roof. Branch vents tie into the main vent. Each and every plumbing fixture and appliance must be vented properly, either by tying into a main vent or by having a vent of its own that extends through the roof. When installing a new fixture in a new location (not just replacing an existing fixture), venting is often the most difficult problem to overcome.

Essential Tools

Plumbing does not require a lot of expensive tools, and even those that you may use for only one job are well worth the cost. The money you save by doing your own work will pay for them many times over. To clear drain lines, get a plunger. The type shown here, with the extra flange extending downward, is ideal for toilets and also works well on bathtubs and sinks. Use a hand-cranked drain auger to clear away clogs that won’t plunge away. For toilets, use a closet auger.

To disassemble and connect pipes and to make many other plumbing repairs, purchase a pair of high-quality tongue-and-groove pliers that adjust to grab almost any size pipe. A standard adjustable pipe wrench is essential for working with threaded iron pipe. An adjustable Crescent wrench will fit the nuts on faucets and other fixtures. To cut pipe, use a hacksaw. Hacksaw blades dull quickly so have extra blades on hand.

For running new pipes through walls, you will need a drill with plenty of spade bits. To cut away drywall or plaster to make room for the plumbing, use a keyhole saw. A flashlight comes in handy when you need to peer into wall cavities and under sinks. For delicate chores such as removing faucet O-rings and clips, have a pair of needle-nose pliers on hand. And have a ready supply of general-purpose tools, including screwdrivers, a putty knife, a utility knife, and a tape measure.

Specialized Tools

Some tools are designed for specialized plumbing tasks. Choose the ones that will help you work with your materials and fixtures. If you will be soldering copper pipe, you must have a propane torch. If you have a lot to do, pay the extra money for a self-igniting model. Otherwise, get an inexpensive spark lighter.

To bend flexible copper tubing without kinking it, use a tubing bender. A two-part flaring tool is necessary if you want to make flare joints in copper tubing. If you plan on cutting copper pipe or tubing, buy a tubing cutter. It makes easier and cleaner cuts than a hacksaw and will not squeeze tubing out of shape. For cutting plastic supply pipes, a plastic tubing cutter makes the job easier. To set the proper incline for drain pipes, you’ll need a level.

When working on faucets and sinks, you will sometimes need a basin wrench to get at nuts you cannot reach with pliers. If you have a damaged faucet seat that needs replacing, don’t take a chance with a screwdriver—use a seat wrench. For those big nuts that hold on the basket strainers of kitchen sinks, you may need a spud wrench. When plunging and augering don’t clear out a clog, a blow bag will often do the trick: hook up a garden hose to it, insert it into the drain pipe, and turn on the water. For large-scale demolition, notching studs and joists, and quickly cutting galvanized pipe, a reciprocating saw makes the job much easier. If you need to chip away tiles to get at plumbing, use a cold chisel.

Log in to comment