First: do you actually need one?
It is worth saying plainly, because a lot of what is written about sump pumps does not apply here.
Most Boerne and Fair Oaks Ranch homes are slab-on-grade. There is no basement, nothing below grade to collect water, and therefore no sump pump — and no reason to install one.
Where they genuinely appear here: houses with crawl spaces that take water in heavy rain, properties on a slope where runoff collects against the foundation, homes with a below-grade garage, storm shelter or wine room, and the occasional older property with a true basement.
If you have one, someone installed it for a reason. If you do not, the answer to drainage problems here is usually grading, gutters and yard drainage rather than a pump — and anyone proposing a sump pump for a slab-on-grade house should be asked to explain exactly what it will be pumping.
Why they fail: the silence problem
A sump pump is unusual among household equipment in that it does nothing at all for long stretches, then has to work perfectly, unattended, at the worst possible moment.
Our rainfall pattern makes this worse than average. Long dry spells followed by intense storms means a pump can sit idle for months and then be asked for sustained duty during a downpour.
Things that fail in storage: the float switch sticks, the impeller seizes, the check valve gums up, the discharge line blocks with debris or a nest, and the outlet quietly loses power without anyone noticing.
None of that announces itself. You find out during the storm, which is the one time you cannot do anything about it.
Worth knowing
The most common sump pump failure is not the pump. It is the float switch — the part that tells it to start. A pump in perfect condition with a stuck float is exactly as useful as no pump at all.
The test that matters, and how to do it
Everything else on this page is secondary to this. Do it twice a year, and before storm season.
Pour water into the pit — a bucket or two, enough to raise the float — and watch the whole cycle. Do not just lift the float by hand; that tests the switch but not whether rising water actually reaches it.
You are checking four things: the pump starts on its own, it moves water at a decent rate, it shuts off cleanly when the level drops, and it does not immediately restart. That last one indicates a failed check valve letting water run back down the discharge pipe into the pit.
Then go outside and confirm water is actually coming out of the discharge point. A pump that runs and discharges nowhere is a blocked line, and you would not know from inside.
The rest of the maintenance
Once a year is enough for these, and none take long.
- Clear the pit. Silt, gravel and debris settle at the bottom and get drawn into the impeller. Scoop it out.
- Check the inlet screen on the pump body for blockage.
- Confirm the float moves freely through its whole travel and cannot catch on the pit wall, the pipe or the power cable. Cable interference is a genuinely common cause of a stuck float.
- Inspect the discharge line along its length and at the outlet. Check for crushing, disconnection, and anything nesting in the end.
- Verify the outlet is live and, if it is on a GFCI, that it has not tripped. Sump pumps get plugged into GFCI outlets that trip silently months earlier.
- Listen while it runs. Grinding or rattling means bearings or a damaged impeller, and that is a warning rather than a nuisance.
Backup, and whether it is worth it
The awkward truth is that the storms most likely to overwhelm a sump pump are also the ones most likely to take the power out. A mains-only pump is unavailable exactly when it is needed.
A battery backup pump runs on its own sealed battery and takes over when the primary loses power or cannot keep up. Whether it is worth it depends entirely on what is downstream of a failure — a damp crawl space is an inconvenience; a finished below-grade room is not.
If you do have one, the battery is a consumable. They typically last three to five years and they fail closed — the system looks fine right up until it is needed. Test it on its own, with the mains unplugged, at the same time you test the primary.
A high-water alarm is the cheapest useful thing in this category. It does not solve anything, but it tells you the pump has stopped keeping up while there is still time to act.