In the US, about 60 million people have septic tanks or private sewage systems. That's about one in five households, with the rest -- over 230 million people -- using municipal or city sewer lines.

If you have a septic tank, its maintenance is completely up to you, the homeowner. If you rely on a municipal sewer line, you're responsible for the section that runs up to the edge of your property.

Regardless of which one you have, a lack of sewer maintenance will lead to plumbing clogs. From slow drains to foul smells to water back-ups, all these can result from clogged drains and sewers.

The question now is, what exactly are the functions of sewer lines anyway? How do they work with your home's drains and what can cause them to get all blocked up?

We'll get you all the answers you're looking for in this post, so be sure to stick around!

A 101 On Your Main Drains and Sewer Line

It's easy to take household drainage systems for granted, as most of the time, we only see the drain fixtures. These fixtures are the visible part of your sink, shower, or tub drains. They're the "black hole" where wastewater begins their journey out of your home.

The thing is, it's quite rare for plumbing clogs to originate from these sections. Except, of course, if food debris, FOG (fat, oil, and grease), as well as small objects, clog the stopper itself. A stopper is often a mesh screen that helps to keep these clog builders from getting into the sewage line.

From here, wastewater then flows into drain lines to P-traps and all the way to the septic system or public sewer.

Drains and P-Traps

Each of your fixture drains connects to a P-trap. It's a pipe that has a straight section immediately followed by a sharp curve, making it look like the letter "P". Your toilets and clothes washer also have their own trap.

Either way, these drain traps hold standing water, which then seals your drain system. They help to keep sewer gases (the gasses that come from the breakdown of waste) stay put in your sewer system. If they didn't, the sewer gases will permeate your home, and it'll end up smelling like rotten eggs.

Drain Lines and Soil Stacks

All your plumbing P-traps attach to a branch drain line that then connects to soil stacks. Drain lines are usually hidden within ceilings, walls, and floors.

Soil stacks, as their name suggests, are the plumbing pipes hidden in the soil outside your home. These are usually right below your lawn or garden. The drain lines empty wastewater (including solids) into the soil stacks.

Soil stacks usually mark the beginning of what you likely know or refer to as the "main drain". From here, they drop your home's wastewater into your septic tank or the municipal sewer line.

As you can see, most plumbing line blockages occur out of sight -- hidden, but otherwise wreaking havoc. Any clog at any of these sections can cause your drains to take a long time to drain, and toilets to take forever to flush.

FOG: The Main Culprit Behind Clogs, Backups, and Sewer Spills

Fats, oils, and grease cause about 65% of sewer backups and spills in the US. That's because when FOG "freeze" or congeal -- along with trash that mixes up with them -- they turn into huge fatbergs. Fatbergs, in turn, block the openings of drain lines, forcing wastewater to go back to where they came from.

Fatbergs cost the US millions of dollars each year -- New York City alone spent more than $18 million at one point. The smaller city of Fort Wayne, Indiana, also shelled out half a million to get their sewers free of grease.

The high cost of clean-up has also triggered public workers in Phoenix, AZ to take steps to keep fatbergs at bay. Pima County has also recently reminded its residents to watch what they flush.

The best way to prevent fatbergs in your own home is to avoid pouring FOG down your drains. Instead, place fats, oils, and grease in a sealed container for proper waste disposal.

In the bathroom or shower, keep your drain screens clear and throw hair into the trash bin. Don't flush anything aside from toilet paper, even wipes that say "flushable" on their label.

If you already have multiple clogged drains at home, your best bet is to get in touch with expert drain cleaners. They use innovative plumbing video technology to figure out the cause -- and location -- of the clogs. As a result, they can clean and clear your drains promptly and with the least disruption.

Sediment Formation: An Overlooked Culprit Behind Drain and Sewer Headaches

Water hardness refers to the water's dissolved mineral (usually calcium and magnesium) content. The higher the rating is, the harder the water. Hard water often doesn't have bad health effects, but it does make cleaning more difficult.

Moreover, these minerals can stick to the inside surfaces of your plumbing pipes. Over time, they'll harden into "limescale". The thicker the limescale gets, the narrower your pipes' hollow interiors become.

The thing is, many parts of Arizona have "hard" or even "very hard" water. Phoenix, for instance, has a 205 to 291 parts per million (ppm) water hardness rating, which is very hard.

That said, you should consider installing a water softener at home if you get really hard water. Aside from the better taste of soft water, it also puts your drain pipes at a lower risk of limescale formation.

One more thing: scientists found evidence that limescale can cause pipe corrosion. If this happens, your water lines and drain pipes will start to leak.

Depending on the severity of the damage, you'd either need to get them patched and sealed. If the damage is too big, however, you may need to get the affected plumbing lines re-piped.

Debris Build-Up On Your Roof

Plumbing vents are vertical pipes that run inside walls all the way to the roof. They allow air to enter a plumbing system. The air, in turn, spreads even pressure throughout the pipes.

Through the help of the air from your plumbing vent, wastewater can leave your home quickly.

However, the opening of the vent on your roof can also get clogged with debris like leaves or even bird nests. Old age can also cause them to corrode and perform less efficiently.

Either way, these problems can reduce the amount of air that gets into your plumbing system. The lack of air can then make your drains and toilets take forever to carry the wastewater out of your home.

Some of the most common symptoms of a clogged plumbing vent are multiple slow drains and toilets. Gurgling or sucking sounds from your sinks also indicate a blocked vent. In any case, it's best to ring up your local licensed plumbers for help.

Tree Roots 'Round Your Pipes

Aside from slow drains and toilet issues, you may have also noticed wet spots in your lawn. You may have even rejoiced because your garden seems to be thriving, even if you didn't really do anything.

Unfortunately, this is an indication that you have a break or a crack in your main drain or sewer line. Tree roots may have wrapped around the pipes, the pressure of which has caused them to burst. As a result, sewage -- which is full of plant food -- has spilled out onto the soil.

This is great for your plants, but not for your plumbing, and most especially not for your property. The damaged pipes can result in sewage and wastewater flowing back to your home. The smell of the sewage itself can attract pests, vermin, and wildlife to your property.

Speaking of pests and vermin, keep in mind that as many as 21 million homes in the US have a rodent infestation. If you don't address your damaged drain main or sewer line, you can become part of this statistic.

More than that, you're putting yourself at risk of the 30+ diseases that rats and mice alone carry and spread!

So, as soon as you noticed any of these signs, don't delay having your sewer line replaced.

Shower Your Drain and Sewer Lines With the TLC They Deserve

There you have it, your comprehensive guide on what a sewer line is, and what it has to do with your home's drains. Now, you know how vital they all are and that they all work together to remove wastewater from your home. That should be enough reason to stop putting them "out of mind" and instead, give them the upkeep they deserve.

If you're dealing with a lot of plumbing problems, know that we here at The Plumber Inc. can come to your rescue. Please feel free to get in touch with us now so we can get all those drains and sewer problems fixed ASAP!