The slow drain that keeps coming back
If you've got a tub that drains a little slower every month, or a toilet that gurgles when the washing machine empties out, you've probably already snaked it once or poured something down there and moved on. Then a few months later it's back. That pattern, slow, clear, slow again, is one of the more reliable signs that something outside the house is narrowing the pipe rather than something inside it clogging the pipe.
In a lot of Republic's older neighborhoods, especially the streets built up through the 50s through 80s around the original downtown grid and the first waves of subdivision off 174 and Highway 60, that something outside is almost always root intrusion into a clay sewer lateral. It's not a flaw in how those houses were built. It's just what clay pipe does over fifty or sixty years when it sits in Ozarks soil next to a maple or a sweetgum that's had decades to get established.
Why clay pipe and tree roots end up in the same spot
Clay sewer line was standard practice for most of the last century, and it's not a bad material on its own. The problem is the joints. Clay pipe comes in short sections, and every joint is a seam, a tiny gap where soil moisture and a faint whiff of sewer gas can escape. Tree roots are built to chase exactly that. A root doesn't need a crack to get in, it just needs a joint that's shifted a sixteenth of an inch, and over a couple of decades of clay in the ground, most joints shift at least that much.
Once a root finds that seam, it doesn't punch through so much as it thickens there, year after year, until it's a fine mesh inside the pipe that catches toilet paper and grease and slows everything behind it. That's why the symptom is gradual. It's not a blockage that shows up overnight, it's a filter that gets denser a little at a time.
More on this from Reading List Tree Roots And The Clay Line Under An Older Yard.
What this area's weather does to the problem
Southwest Missouri doesn't get the deep frost line some northern states deal with, but Republic still gets real freeze and thaw cycles most winters, and that matters for clay pipe. Ground that freezes, thaws, freezes again shifts a little each time, and clay joints that were snug in October can be loose by March. Then spring brings the heavy rain Greene and Christian County are known for, and saturated clay soil swells and settles unevenly, which opens those joints up even more.
Summer does its own damage from the other direction. When we get a stretch of dry weeks in July and August, which happens most years, the clay soil here shrinks and cracks. Tree roots respond to that by pushing harder toward any source of steady moisture, and a leaking sewer joint is about the most reliable water source around in a dry month. So the line takes a hit twice a year, from opposite directions, and that's part of why these older Republic lots see root problems more than newer construction on PVC.
What you can actually check yourself
Start by noticing which fixtures back up first. If it's the lowest drain in the house, a basement floor drain or a ground-floor shower, before anything upstairs, that's a strong hint the problem is in the main line headed to the street, not in a branch line under one sink. Multiple slow drains acting up around the same time is another tell, since a single clogged trap only ever affects one fixture.
Walk the yard between the house and the street and look for a patch of grass that's noticeably greener or lusher than the rest, even in a dry spell. That's often sewage leaking slowly from a cracked joint and fertilizing the ground above it. Also worth noting: if you've got a mature tree, especially a silver maple, willow, or sweetgum, within twenty or thirty feet of where your line runs, assume it's a candidate even if nothing's gone wrong yet.
What you shouldn't do yourself is guess at the location and start digging, or dump a jug of root-killing chemical down the toilet as a first move. Those products can slow new growth but they don't clear out what's already matted inside the pipe, and digging blind in a yard that's never been located risks hitting the line itself, a gas line, or a buried cable.
Where this stops being a DIY job
A plumbing inspection with a camera is the only way to actually see what's happening inside an old clay line, rather than guess from symptoms. It shows exactly where the roots have gotten in, how bad the damage to the joint is, and whether this is a spot clearing job or a sign the whole lateral is due for replacement. That distinction matters a lot for an older Republic home, because a line that's otherwise sound might just need the current blockage cut out, while a line with multiple failed joints is going to keep producing the same problem every year or two no matter how often it's cleared.
If you're buying an older house in town, or you've owned one for a while and never had the sewer line checked, that's worth doing before it becomes an emergency. A slow drain on a Tuesday is an inconvenience. A backed-up line on a holiday weekend with family in the house is a different problem entirely, and it's the kind of thing a camera inspection is built to catch ahead of time.