Plumbing 101
How Your Home’s Plumbing Works
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A few months ago, while I was taking a shower, my toilet began making glugging noises.
After I got out of the shower and dried off, I cautiously lifted the toilet seat and took a peek.
All seemed to be well.
I flushed the toilet. That went fine.
I stepped over to the bathtub, turned the faucet on full blast, and went back to the toilet to observe the result.
After a minute, the water in the toilet bowl began to glug.
I hastily shut off the bathtub faucet. After 15 seconds, the glugging stopped.
But I knew what it meant.
After 30 years of renters showering off God-knows-what down the bathtub drain, and flushing God-knows-what down the toilet, the main drain was clogged.
Using the bathtub, washer, and dishwasher was off-limits until the clog was cleared. Flushing was on an emergency basis.
I called the plumber at 7 am the following morning. He arrived at 8. Because the house had no accessible cleanout, he had to dig a hole in my front yard and install a cleanout and cap on my sewer line.
Luckily, because I understood plumbing basics, I recognized the problem before my toilet became a geyser.
Plumbing Basics
You don’t need to know how to install plumbing to keep your home’s plumbing systems in good repair. You need two things—an understanding of how your home’s plumbing works and a reliable plumber.
This post will help you with the first thing. For the second, this post will help you build a trades list, including a plumber.
Your home’s plumbing is composed of three systems:
Water in: clean water is delivered to your home under pressure
Water out: wastewater is carried away from your home via gravity-fed drainage lines
Venting: allows the drainage system to work properly without blowback (which is very bad).
You may wonder why I know anything about plumbing.
When I was growing up in a Pittsburgh suburb, my dad was chairman of the board of our local sewer company for over a decade. His children called him The King of Shit.
I learned the basics by overhearing my dad’s occasional nighttime phone conversations with the staff at “The Plant” or irate local citizens experiencing an issue.
I learned the rest while renovating my homes and dealing with a variety of exciting plumbing challenges.
Water In
Under Pressure
I’m always surprised to hear that people have no idea that their clean water is delivered to their homes under pressure to push water throughout your home.
Water pressure is measured in PSI (pounds per square inch). According to my plumber, the generally recommended residential water pressure is 40 to 60 PSI, with 60 PSI being ideal for most homes. Above 80 PSI, your plumbing and appliances that use water are at risk for leaks and burst pipes.
Don’t assume that your clean water utility keeps its PSI at a steady 60. To ensure that water reaches every customer that needs it, clean water utilities may need to deliver water at a PSI higher than 60 to overcome high-elevation and other system demands.
When my plumber assessed my home’s 70-year-old plumbing, he discovered that the clean water coming into the house was at 120 PSI. He hastily installed a pressure-reducing valve (PRV) which keeps the water coming into my home at 60 PSI (and the pipes intact).
I later discovered from a water bureau service person that the water pressure was set at 120 PSI to accommodate the enormous water demands created by a recent luxury home-building project in my ‘hood.
If you want to check your water pressure, buy a screw-on water pressure gauge, attach it to your outdoor hose spigot, make sure that no one is running water in your home during the test, turn the spigot on full blast, and read the dial. Because water pressure can fluctuate, take several readings during the day.
When You Need It
Your home’s water supply plumbing has two jobs—to carry pressurized water to where you need it and then convince it to stop until you need it. These tasks are accomplished via the pipes in your home and the valves at the end of each pipe.
Valves? Where or what are these valves?
Every device in your home that uses water—including your faucets, toilets, washing machine, and dishwasher—utilizes at least one valve to control water flow.
Here are a few examples:
Sink faucet: the faucet handle opens/closes or adjusts an internal valve/cartridge, allowing pressurized water through the spout. With a mixer faucet, the handle(s) also controls the proportion of hot and cold water.
Shower faucet: Same basic concept as a sink faucet, but the mixing valve has the additional job of controlling the hot/cold mix; modern shower valves may also protect against sudden temperature changes.
Toilet: toilets have two valves doing two completely different jobs. The fill valve lets pressurized water refill the tank, then shuts it off when the tank reaches the correct level. Flushing uses another valve to release the stored tank water into the bowl; then the fill valve goes back to work.
Washing machine/dishwasher: An electrically operated inlet valve opens when the appliance calls for water and closes when it has enough.
What happens when a pipe or a valve fails, for example, a pipe that freezes and then bursts?
Your very own indoor flood. Definitely not recommended.
Why Hot Water Takes so Long
When water is delivered to your home, your home’s pipes branch off to deliver cold water directly to fixtures and appliances and to the cold-water inlet of your water heater.
When you open a hot water faucet, pressurized cold water enters the water heater. That incoming water displaces hot water in the water heater tank, forcing the hot water to leave the heater through its hot-water outlet. The hot water travels through the hot-water piping in your home to the faucet.
Why does it feel like it takes ten minutes for hot water to come out of the faucet?
Because the water coming into your home is under constant pressure, your home’s pipes are always full of water. Which gets cold while waiting for its debut at the faucet.
Basically, the cold water sitting in the hot-water pipe has to come out of the faucet before the hot water from the heater can reach you.
Yes, it pisses me off, too. Especially since my bathroom is on the other side of the house from the water heater.
There are several ways to reduce your hot-water waiting time. The simplest is to ask your plumber to install a small point-of-use mini-tank water heater at the fixture.
When You Want to Make the Water Stop
Shutoff valves cut off the water flow to a specific faucet or water-related device. The most common scenario for using a shutoff valve is when you need to replace or repair a faucet or water-related device and want to stay dry.
Shutoff valves are all over your home. You’ve probably seen these even if you didn’t know what they were.
Main shutoff valve: the big one that shuts off water to your entire home. If you only know where one shutoff valve is, this should be the one. Your main shutoff valve is usually located near the point where the water supply line enters your house. If you don’t know where your main shutoff valve is located, stop reading this post and find it. Seriously. Knowing where mine was kept my house from being completely flooded due to a burst pipe.
Fixture shutoff valves: the little valves under sinks and behind toilets and washing machines that let you isolate one fixture instead of shutting down the whole house.
Pressure-reducing valve (PRV): mentioned in the Under Pressure section above, this valve will safeguard your pipes and water-based devices from damage due to too-high PSI.
Water-heater shutoff: controls the cold-water supply to the heater, not the whole-house main.
Also, before working on a faucet or water-related device, test the shutoff and make sure the water has actually stopped.
Water Out
After you (or a water-using appliance) use the water that comes out of the faucet, and that water goes down the drain, it begins its journey away from your home.
When wastewater enters your home's drainage system, gravity takes over. Here’s the process:
Traps: in sinks, bathtubs, and showers, wastewater first passes through a curved pipe called a P-trap. Toilets have a trap built into the fixture. Dishwashers and washing machines also ultimately drain through trapped plumbing. Why so many traps? Because traps have a bend in them that holds a small amount of water to block sewer gases from coming up into your house. Very helpful.
Branch drains: from the trap, the wastewater moves through the branch drainpipes in your home, which join progressively larger drainpipes that eventually connect to the home's main drain, which connects to the sewer line, allowing wastewater to flow into your municipality’s sewer system. If you live in a rural area, your wastewater empties into an underground septic tank in your yard.
City sewer system: your municipality maintains a network of underground pipes that carry wastewater to a treatment plant (like “The Plant” referred to above), where the water is treated and ultimately returned to a local river or lake. If you have a septic system, it will allow the liquid wastewater to flow into a drain field to be filtered by the soil.
Since wastewater moves by utilizing gravity—not pressure—wastewater pipes are generally larger in diameter than fresh water pipes.
My toilet gurgling experience covered in the introduction is an example of what happens when wastewater flow is interrupted by a main drain blockage.
Venting
Have you ever noticed the little pipes sticking out of your roof? Some of those pipes are plumbing vent pipes.
Venting is critical to getting wastewater out of your home. Your home’s venting system regulates the air pressure inside your home’s drainage pipes to keep wastewater flowing smoothly.
As wastewater moves through drainpipes, it can create pressure changes, including negative pressure behind the flowing water. Plumbing vents allow air into the drainage system to equalize the pressure and avoid creating a vacuum in a drainage pipe.
When a vacuum is created in a drainage pipe, several things can happen, including wastewater drainage slowing down, wastewater backing up, and water being pulled out of your drainage system’s traps, releasing sewer gases into your home.
All of which are very, very bad.
Plumbing vents also allow sewer gases to escape from your home’s drainage system above your roof and away from your nose.
Safe to say that venting is critical, yes?
Since vent pipes are essentially exposed to the elements, they can be damaged or clogged by leaves, snow, ice, dirt, or even animal nests. If that happens, you may experience slow drainage, gurgling sounds, poorly-draining toilets (yikes), and even sewer odors—all indicating that it’s time to call your plumber.
When to Call a Plumber and When to DIY
Your home’s plumbing is pretty easy to understand. Some plumbing issues can be addressed with a little DIY. Some require specialized expertise and equipment to fix.
Plumbing DIYs
A toilet that keeps running, which can waste a lot of water. This can be an easy DIY fix if the problem is in the toilet tank. Check your toilet manufacturer’s website for instructions on how to troubleshoot your issue.
A clogged bathroom drain. In most cases, if the sink is simply clogged with hair, I’ve found that this little plastic drain-cleaning tool does the trick. Or, you can get a “variety pack” of drain-cleaning tools for a few dollars more. If the clog is stubborn, try a mini-sink plunger.
For a clogged toilet, a good toilet plunger is an excellent first step.
A dripping sink faucet may simply need to have worn internal parts replaced. Consult the faucet manufacturer’s website for guidance.
Call the Plumber
Water stains, damp spots, or unexplained moisture—especially on ceilings, walls, cabinets, or around fixtures—that can indicate hidden supply and drain leaks.
Water where there shouldn’t be any, for instance around a toilet, under a sink, or around a water heater.
Water backing up into another fixture—like my bathtub and toilet example at the beginning of this post.
Sudden low water pressure or a sudden significant spike in your water bill. Either can signal an unnoticed and significant leak.
Sudden appearance of sewer odors (we’ve discussed this).
Drain and toilet clogs that you can’t clear, or clogs that recur after they are cleared.
No hot water or a leaking water heater. If either happens to you, turn off the water to the hot water tank immediately—before you are forced to build an ark—then investigate the cause.
One caveat to all of the above: if you have an uncontrolled, supply-side leak (i.e., incoming water), like a broken or burst pipe, turn off the water at the main valve before calling the plumber.
When you boil it down, plumbing is all about how water flows in and out of your home:
Pressurized water comes into your home.
Your home’s supply-side pipes carry the water where you need it.
Access to incoming water is controlled by a valve at the end of each pipe that’s usually operated by a faucet.
In addition to those valves, you can also stop the incoming water using one of several shutoff valves located in your home.
Wastewater utilizes gravity to exit your home via your home’s drainpipes.
Your home’s venting system regulates the air pressure inside your home’s drainage pipes to keep wastewater flowing smoothly to your city’s sewer system.
Knowing the basics about your home’s plumbing will help you to prevent plumbing-related emergencies and better navigate them when they happen.
Hey, have you located your home’s main shutoff valve yet?
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