That ghost flush at 2 a.m.
You hear it before you're fully awake. A low hiss, then a gurgle, then a longer fill cycle than any toilet should need if nobody's touched it in hours. In a lot of houses around Nixa this happens most in late summer and early fall, when well pressure and municipal pressure both shift with the season, and it's easy to write it off as the house settling or the pipes being weird. It's not the house. Something inside the tank is letting water sneak past it, drop by drop, until the tank senses the loss and refills to make up for it. That refill is what wakes you up.
This is sometimes called a phantom flush, and it's one of the more common calls a plumber gets from homes in this area, especially the ranch-style and split-level houses built in the 60s through the 80s that make up a lot of the older Nixa neighborhoods. Those toilets have had a few decades of mineral-heavy water working on their internal parts, and Ozark water, whether it comes from a well or from the city system pulling off Sac River sources, tends to run harder than what you'd get on either coast.
What's actually leaking
Nearly always the culprit is the flapper, the rubber or plastic flap at the bottom of the tank that's supposed to seal the tank off from the bowl between flushes. Over time that flapper hardens, warps, or picks up a coating of mineral scale, and it stops sealing flush against the drain opening. Water seeps through in a slow trickle you'd never notice during the day, but overnight, with nothing else running in the house, the drop is enough to trip the fill valve.
The other common source is the fill valve itself, the taller mechanism usually on the left side of the tank. If it's not shutting off completely, or if the float is set wrong, it can let a trickle through even with a good flapper. Less often, the problem is a crack in the overflow tube or a fill tube that's aimed wrong and dribbling water down the overflow constantly.
More on this from Reading List A Toilet That Refills By Itself Overnight.
What you can check without any tools
Take the tank lid off and drop a few drops of food coloring into the tank water, then don't flush. Check the bowl in twenty minutes. If color shows up in the bowl without a flush, you've confirmed it's the flapper or the seal beneath it, not something upstream in the supply line.
While the lid's off, look at the flapper itself. Hard, curled edges or a chalky white buildup around the rim are common signs, especially in houses on well water or in the older parts of town where the plumbing hasn't been updated. Also look at the water level in the tank. It should sit about an inch below the top of the overflow tube. If it's higher than that, water is constantly spilling into the overflow and down into the bowl, which will read the same as a bad flapper from upstairs in bed.
The fix that's genuinely a homeowner job
Replacing a flapper is one of the easier repairs in the house. Shut off the supply valve at the wall, flush to empty most of the tank, unhook the old flapper from its pegs, and take it with you to match the size and shape. Flappers aren't universal, and a mismatched one will just cause the same problem again in a different way. Most hardware stores in the Springfield and Nixa area carry the common two- and three-inch sizes. This is usually a job that costs a few dollars in parts and takes less than half an hour, not something that requires a truck to show up.
When to stop and call somebody
If a new flapper doesn't stop the leak, or if the fill valve keeps running no matter how you adjust the float, that points to a problem inside the valve assembly or, less commonly, a crack in the tank itself. Cracks are more of a concern in older homes where the toilet has been through a freeze event, and Nixa gets enough hard winter nights that a crack from years back can slowly worsen. Any sign of water pooling at the base of the toilet, not just noise from the tank, means it's time to call a plumber rather than keep swapping parts. And if your water has heavy sediment or you're on a private well with known hard water, a plumber can also check whether the supply line and shutoff valve are contributing, something that's hard to diagnose without taking things apart.