Understanding home plumbing systems is essential for performing routine maintenance, diagnosing problems and planning a remodel. The system has two parts that deliver clean water and remove wastewater: supply lines and drain pipes.
Water flows under pressure along supply pipes to toilets, faucets and other fixtures. Behind the walls at some fixtures are air chambers that trap a column of air to cushion onrushing water and prevent damage from water hammer.
Water Supply
The water supply system transports clean, treated water from a central source like a water treatment plant or reservoir to homes and businesses via pipes. It includes a main water line, water meter, and shutoff valve located on the street-side of your house (or in a basement or crawl space if your home is built on a slab). It also includes a network of pipes that carry potable water throughout your home.
The plumbing systems in your home depend on the water supply line to provide adequate water pressure at all times. Properly sized supply lines ensure consistent water flow and prevent problems such as water hammer, which can damage your pipes over time. It is important to assess your supply lines and consult with professionals to determine the appropriate size for your home or business.
The drainage system consists of drainpipes that transport wastewater and sewage from sinks, toilets, showers, and appliances to the municipal sewer system or septic tank. It also includes a venting system that maintains proper air pressure in the plumbing system and keeps sewer gases from entering your home. Finally, it includes traps that retain a small amount of water to prevent sewer gases from backing up into your home or plumbing fixtures. Proper plumbing minimizes pollution and contamination of natural water sources, and it ensures safe drinking water for all.
Drainage
Drainage is what allows water to flow through pipes and out of fixtures, but it’s also important for preventing clogs. Clogged drains are a serious plumbing issue that can lead to expensive repairs, water damage, and health risks. To avoid them, you need to be careful what you put down the drains, regularly clean out your gutters, and keep an eye on your drainage system during severe storms.
Most plumbing drainage systems consist of a network of pipes that collect waste and wastewater. The pipes are sized to accommodate the expected water volume and flow rate. For example, a larger pipe can handle more wastewater than a smaller one, so it’s important to follow the relevant building codes and regulations when choosing your pipes.
The drains themselves have special traps that help prevent clogs. These traps are usually called S-traps or P-traps, and they work by collecting dirty water and sealing the pipe. S-traps are usually used in toilets, while P-traps are often found in sinks, tubs, and showers.
The wastewater is then collected in a sewer system that carries it away to a sewage treatment plant. In some cases, a drainage system may be connected to the sewer line to prevent sewage from backing up into homes. This is especially true in areas with older plumbing systems that are prone to clogs and blockages.
Septic System
Septic systems are common in rural areas where sewer systems don’t exist, and they take advantage of natural processes to treat household sewage. They consist of an underground tank that collects wastewater and a drain field to purify it before it enters the soil. A septic system typically costs less to install than a sewer line, and it’s cheaper to maintain. However, septic systems can still clog or have trouble during heavy rain, which is less of an issue with municipal sewer lines.
When a septic system is functioning properly, waste water flows from household plumbing into the septic tank, where microbes break it down and purify it. The wastewater then exits into the drainfield via a network of underground pipes. The gravel and soil in the drainfield act as biological filters to purify sewage before it enters groundwater or surface water.
If a septic tank becomes clogged or fails to process waste, it can cause dangerous bacterial contamination of nearby drinking water and the environment. Common septic tank failure symptoms include slow-flushing toilets, plumbing backups and foul odors.
Avoid septic tank problems by only flushing human waste and toilet paper, and by disposing of food scraps, oils, grease and automotive chemicals in the trash rather than the toilet. Other items that shouldn’t be flushed include cigarette butts, which can block the inlet baffle, and cat litter, which clogs toilets and siphons.
Water Heater
The water heater is a plumbing appliance that heats incoming cold water to warm it for use in sinks, showers, clothes washers, dishwashers, and other appliances. It also stores hot water for use as needed.
The water heater has a dip tube that brings in cold water to the bottom of the tank, and a heating burner/element that warms the water. Since hot water has less density than cold water, it rises to the top of the tank as it gets warmer. When the desired temperature is reached, a hot water supply pipe takes it from the top of the tank and sends it to your home’s faucets or other plumbing fixtures.
Like other parts of the plumbing system, the water heater and the water supply pipes are susceptible to mineral and sediment buildup over time. This buildup causes hard water, which can lead to slow draining and low or uneven water pressure. The deposits create rough surfaces that trap other materials that pass through the pipes, such as hair, soap scum, and grease, leading to stubborn clogs.
The water tank is usually located in a basement or other lower level of the house, and a copper, iron, or steel pipe leads from it to the drainage system. It’s a good idea to have this pipe extend at least 6 inches above the floor, and building codes often require that it be braced against movement from earthquakes and other natural events.