The small plumbing issue that can ruin move-in week
Most homebuyers picture the “big” stuff: roof, foundation, HVAC. But the first surprise bill after you get the keys is often plumbing. A slow kitchen drain, a toilet that never quite stops running, or a water heater that’s limping along can turn your first week in San Antonio, TX into a string of hardware store trips.
A plumbing inspection is basically a reality check before you close. Not because every house has problems, but because the plumbing system is used every day, hidden in walls, and expensive to access once you’re moved in. The goal isn’t perfection. It’s knowing what you’re buying, what needs attention soon, and what could become an emergency.
What a plumbing inspection actually covers
A plumbing inspection goes deeper than “does the water turn on?” It’s a focused look at the parts of the home that move water in, carry wastewater out, and protect the home from leaks.
You’ll typically get eyes on water supply lines (the pipes that bring clean water into sinks, showers, and appliances), drain lines (the pipes that carry used water away), shutoff valves, visible pipe connections, and fixtures like toilets and faucets. A plumber also pays attention to signs of past leaks, corrosion, and DIY repairs that look fine until pressure or daily use exposes a weakness.
It can also include checking the water heater for age, safety issues, and performance, since it’s one of the most common “works today, fails next month” items in a purchase. And if the home has older plumbing materials or a large yard tree line, a sewer check may be recommended, because repairs outside the home can be some of the priciest.
Why problems slip past a standard home inspection
A general home inspection is valuable, but it’s broad by design. The inspector is checking many systems quickly, and plumbing often gets a basic functional test: run a few faucets, flush toilets, look for visible leaks. That’s a good start, but it doesn’t catch the sneaky stuff that causes real damage.
Here’s what tends to get missed without a plumbing-focused look:
A small leak under a sink can be hidden by stored items or a recently cleaned cabinet. A drain can “seem fine” with a quick run of water, yet still have a partial clog that backs up during dishwashing. Older shutoff valves can be seized (stuck in place), which you don’t discover until you need to stop a leak fast. Even a decent-looking bathroom remodel can hide mismatched parts or improperly vented drains, which can lead to gurgling, slow drainage, or sewer odor.
Plumbing is also very dependent on conditions you can’t see in a quick walkthrough: water pressure, pipe condition inside the walls, and the health of the sewer line leaving the home.
A practical plumbing inspection checklist before you close
This is the kind of hands-on checklist that helps you avoid surprises, whether you hire a plumber or do a first-pass walkthrough yourself:
- Find and test the main water shutoff to confirm it turns smoothly and fully stops water
- Check under every sink for dampness, swollen particleboard, or crusty mineral deposits around fittings
- Run hot and cold water at each faucet and watch for sputtering, weak flow, or long delays for hot water
- Flush every toilet and listen for slow refills, ghost running, or wobbling at the base
- Fill and drain tubs and sinks to see if water pools, drains slowly, or causes gurgling sounds
- Look around the water heater for rust, water staining, a temperature/pressure relief valve discharge pipe, and any signs of active leaking
- Run the dishwasher and washing machine fill cycle if possible, and check the hoses and shutoffs behind them
- Step outside and look for overly lush patches, soggy spots, or sewer cleanout caps that look broken or recently disturbed
- If the home has big trees or is older, ask about a sewer line inspection option before closing
Pressure, flow, and hard water: what’s normal and what’s a warning
A lot of buyers confuse pressure and flow, and that’s where bad assumptions happen.
Water pressure is the force pushing water through the pipes. Flow is how much water comes out of the faucet over time. You can have strong pressure but poor flow if something is restricting the water right at the fixture, like a clogged aerator (the small screen at the end of the faucet spout) or mineral buildup in the cartridge inside the handle.
If a faucet feels weak, it’s tempting to blame the whole house. But sometimes it’s just one fixture that’s restricted, and that’s a cheaper fix than you’d think. When you’re shopping for replacement faucets later, look for models that balance performance and savings. The EPA’s WaterSense program sets a maximum flow rate for labeled faucets and aerators to help reduce water waste without making daily use miserable, and it’s a solid benchmark when comparing options at the store (WaterSense faucet flow guidance).
Now for the local reality: hard water. Hard water means there’s a higher level of dissolved minerals, mainly calcium and magnesium. Those minerals can create scale (a chalky buildup) inside faucets, on showerheads, and in water heaters. In San Antonio, TX, the local utility notes that water hardness commonly ranges around 15 to 20 grains per gallon, which is considered very hard and can speed up buildup in plumbing components (SAWS water hardness range).
Hard water doesn’t automatically mean “bad plumbing,” but it does mean you should expect more maintenance: cleaning aerators, replacing faucet cartridges sooner, and paying attention to water heater performance. In a home purchase, hard water becomes important because it can hide the real condition of fixtures. A faucet that barely flows might just be scaled up, or it might be failing internally. A good plumbing inspection helps separate “needs cleaning” from “needs replacement.”
If the inspection uncovers trouble, what to do next
Finding plumbing issues before closing is actually a win, as long as you handle it the right way.
If the shutoff valve is stuck, don’t force it. Snapping a valve stem can turn a simple fix into an emergency. Instead, note it and have it replaced correctly.
If there’s corrosion on visible piping, resist the urge to sand it or coat it with a sealant “to stop leaks.” Corrosion is often a sign of age, moisture history, or dissimilar metals reacting at a connection. Covering it can hide an active leak and make it harder to spot later.
If drains gurgle or smell, don’t dump chemicals down them. Many harsh drain cleaners generate heat and can damage older pipes or worsen weak joints. Gurgling can point to a partial blockage or venting issue (a vent is the pipe system that lets air into drains so water flows smoothly). Sewer smell can come from a dry trap (the water seal in a drain that blocks sewer gas), but it can also suggest a vent or sewer problem worth investigating.
Water hammer is another one to treat carefully. That loud banging when a faucet shuts off fast is usually caused by a sudden stop in water movement. Sometimes it’s minor and solved with a simple adjustment or an arrestor (a small device that absorbs the shock), but sometimes it’s a sign of pressure issues or loose piping.
When you find a problem, the next best step is to document it, decide whether it’s a repair request or a negotiating point, and avoid quick fixes that could muddy the real condition before you close.
How to verify the home is truly ready after fixes
If the seller agrees to repairs, you want to confirm the problem is actually resolved, not just cosmetically hidden.
Start with a slow, patient leak check. Open the cabinet under sinks and feel around the supply connections and drain trap (the curved section of pipe under the sink that holds water to block sewer gas). Dry everything with a paper towel, then re-check after running water for a full minute. Even a tiny seep will show up.
For drains, run water longer than you think you need to. A partial clog might not show until the pipe is carrying a steady load. Fill a sink halfway, then release it and watch how it drains. While it’s draining, listen for gurgling in nearby fixtures, which can hint at venting or drain restrictions.
For toilets, flush once and wait. Then flush again a minute later. That second flush is where weak fill valves and slow refills show their true colors.
For the water heater, confirm hot water arrives at a normal pace and stays consistent. If you get 30 seconds of warm water and then it goes cold, that’s a red flag. Also look for moisture around the base and at the connections above the unit, because small leaks often start there.
Finally, give the plumbing a few days if you can. Even after closing, keep the under-sink cabinets empty for a short time so you can spot new drips early instead of finding a warped cabinet bottom later.
When calling PlumbSmart saves you money and stress
If you’re trying to decide whether a plumbing inspection is worth it, think about this: plumbing problems are expensive mainly because they hide. You’re paying for time to locate the issue, access it, and repair it without causing more damage.
A targeted inspection is especially helpful if the home is older, has large trees, has had recent remodeling, or shows signs of slow drains and past leaks. Those are situations where “it works during the showing” doesn’t mean it will keep working after daily use begins.
If you want a professional set of eyes before you close, PlumbSmart can help you get clarity fast, from basic fixture concerns to deeper system checks through our plumbing services in San Antonio. If moisture stains or musty cabinet smells show up, it’s worth looking into leak detection and repair before they turn into flooring damage.
And if the home has gurgling drains, frequent backups, or you’re buying in an area with older lines, a sewer video inspection can reveal cracks, root intrusion, or bellies (low spots that collect waste) that you simply can’t confirm from inside the house. For homes with an aging unit or questionable performance, planning ahead with water heater maintenance can prevent the classic “new house, cold showers” surprise.
One more tip that buyers rarely hear: if you replace any fixture after moving in, choose components meant for drinking-water contact. Faucets, valves, and fittings should be made from materials tested to reduce the risk of chemical contaminants leaching into water. NSF/ANSI 61 is a key standard used for that kind of material safety in drinking-water system components (NSF/ANSI 61 standard overview).
A simple way to decide before you sign
Yes, a plumbing inspection is worth it for many homebuyers, because it gives you leverage and peace of mind at the exact moment you still have options.
If you want to make the smart call without overthinking it, focus on three actions. Confirm the fit of the system to the home (water heater age, shutoff access, drain behavior). Prioritize reliability (no hidden leaks, no questionable DIY connections, fixtures that work smoothly). And plan for real-world conditions like hard water buildup and drain wear, because those don’t wait politely until you’re settled.
Get those three right, and you’ll move in with confidence instead of crossing your fingers every time you turn on the tap.
