The pipe out front you've never looked at
If you're reading this, you probably just had water back up into a tub or a floor drain, or you're trying to get ahead of it before it happens again. That cleanout you've been meaning to find is a short length of pipe with a screw cap, usually capped in white or black plastic, sticking up a few inches out of your yard or sitting low against your foundation. Most people in Nixa never notice it until the day they need it, and by then they're standing in an inch of water trying to find it in the dark with a phone flashlight.
That's the wrong time to go looking. A calm Saturday afternoon is the right time, and it takes maybe fifteen minutes.
Why Nixa yards hide them well
A lot of the housing stock here went up from the 1970s through the 2000s, as the town grew out from the square along 160 and Massey Boulevard. Depending on when your section of town was built, your cleanout might be a short stub near the foundation, or it might be out near the street where the lateral line meets the city main. Older homes closer to downtown sometimes have a cleanout tucked against the house under a porch or deck addition that came later, which covers it up entirely.
Newer subdivisions built on the clay-heavy soil common to this part of southwest Missouri tend to have cleanouts set flush with the yard, and over a few mowing seasons they get buried under an inch of turf and soil. If your yard has had any grading, mulch beds, or landscaping added since you moved in, there's a decent chance yours is sitting under something.
More on this from Reading List Find Your Cleanout On A Calm Afternoon, Not During A Backup.
What to actually check this weekend
Start at the foundation wall closest to your kitchen or main bathroom line and walk the perimeter looking for a capped pipe low to the ground. Then check the yard between your house and the street, especially near where you'd guess the sewer lateral runs. A metal detector isn't necessary, but a probe or even a stiff screwdriver poked gently into soft, suspicious patches of grass can find a buried cap faster than digging blind.
If you genuinely can't find one, check your home inspection report from when you bought the place. Inspectors in this area usually note cleanout location, and it's an easy detail to overlook later. County or city permit records can sometimes help too, since sewer lateral work gets documented.
Once you find it, don't open it. Just confirm it turns, note where it is, and maybe mark it with a small stake or flag so you're not searching the lawn again under worse conditions.
What Ozark weather does to the pipe between here and the street
The ground here freezes and thaws more than people expect for Missouri, especially on clay soil, and that freeze-thaw cycle shifts pipe joints over the years. Add in the heavy spring rains that come through the region, sometimes dumping a few inches in a single afternoon, and tree roots from mature oaks and maples common in older Nixa neighborhoods looking for any moisture source they can find, and you've got the two most common reasons sewer laterals back up around here: root intrusion and soil movement cracking old clay or cast iron pipe.
Backups tend to cluster in spring after saturated ground and in late summer when root growth is most aggressive. If your home was built before the 1990s, there's a reasonable chance at least part of your lateral is original clay tile, which is more vulnerable to both problems than the PVC used in newer construction.
Where this stops being a weekend project
Knowing where your cleanout is and confirming it opens is well within homeowner territory. So is keeping grease out of your kitchen line and watching what you flush. But once water is actually backing up, the job changes. Opening a cleanout under pressure from a blocked line can send sewage back at you fast, and running a snake into a line you don't understand can push a problem further down rather than clearing it.
If you've found the cleanout, tried a plunger or basic auger on an indoor fixture, and the backup keeps returning, that's the point to call someone who can run a camera down the line. A camera inspection will tell you whether you're dealing with roots, a belly in the pipe from ground settling, or something that needs excavation, and guessing at that from the surface wastes time and money. In a town where a good share of the lateral lines are pushing forty or fifty years old, getting an actual look at the pipe is worth more than another bottle of drain cleaner.