How Home Plumbing Systems Work
When was the last time you thought about your plumbing? Not like, “I really need to scrub that toilet” or “I wonder what it would cost to replace that showerhead”—but really thought about it? Our guess is, despite the fact that indoor plumbing is something of a miracle, you’ve spent very little time marveling over it. Appreciating it. Understanding how the parts all go together to bring you safe, freshwater every single day. OK, sure. We’re Pittsburgh’s most trusted plumber, so we’re admittedly a bit enamored with plumbing things. But we think it’s important that every homeowner has a general idea of how plumbing systems work.
When your plumbing’s doing its job well, it’s not terribly important to understand how. But if something goes wrong, it can be extremely helpful to know the basics so you can more efficiently troubleshoot and more effectively share information with us when you call for help. Fortunately, it’s not rocket science. Although it does involve gravity.
The Two Major Plumbing System Components
Your plumbing system serves two major functions: It brings freshwater into your home, and it removes wastewater from it. Let’s break each of those down.
How Freshwater Enters Your Home
Whether you’re connected to your city water supply or you have a private well, water comes into your home the same way: under 50-60 psi of pressure and through (typically) 1” or 1-1/2” copper pipes. At the point of entry, you’ll find your water meter (if you’re on city water) on the outside and your water shut-off valve on the inside.
Aside: If you haven’t located and checked your water shut-off valve recently, take a quick break from reading this post and go do that right now. It’s that important. Everyone in your home should know where that valve is and how to turn it off. (Righty tighty!) If a pipe bursts, your first line of defense against major damage is that valve.
Once inside, the main water supply line splits into several runs. One goes to your hot water heater, which is connected to another series of pipes that delivers heated water wherever it’s needed. The rest of the lines serve your cold water taps in your kitchen, bathroom, laundry room, and so on.
Freshwater has to be under pressure to make it to all of those locations—around corners, down long hallways, and upstairs. But it can’t be under too much pressure, or your pipes could rupture.
How Wastewater Leaves Your Home
Wastewater from sinks, showers, toilets, and appliances goes to your Drain-Waste-Ventilation (DWV) line. The DWV takes wastewater away from your home and to your septic tank or to the city sewer line and, eventually, to the wastewater treatment facility.
Unlike your water supply line, the DWV does not work under pressure; rather it works under gravity. In a properly plumbed home, all wastewater pipes slope at a rate of ¼” per foot of pipe. If the slope is too gentle, you’ll experience backups and clogs; if it’s too steep, water will move too quickly to take solids with it.
Under each drain, you’ll find a trap. These u- or s-shaped sections of pipe connect each fixture to the DWV line. They stay filled with water at all times (take that, gravity!), which “traps” noxious gases and prevents them from traveling through the line, out the drain, and into your otherwise fresh-smelling home.
Another critical component of your DWV is the vent. An open-ended pipe that protrudes through the roof of your home, the vent regulates pressure in the DWV line, which ensures wastewater continues to move through the entire system—and out of your home. It also provides an escape for sewer gases.
Finally, DWV lines are required to include cleanouts, which provide quick access to the line in the event of a major clog. Inside, cleanouts are located in the wall or floor, usually at a 90-degree bend in the line. Outside, cleanouts are located along the sewer lateral line; they’re typically white with a threaded cap. Protip: Do not open an interior cleanout without a bucket underneath.
When Things Go Wrong
Although the basic mechanics of how plumbing systems work are fairly simple, there are a number of opportunities for things to go wrong. Pipes can rupture, leak, and clog. Fittings can wear out. A vacuum in the system can pull all the water out of your traps, leaving sewer stink behind. Whatever your plumbing situation, Taggart Plumbing is here to help. Call us today!