What We Look For (And What We Don’t): Plumbing Walkthrough — How We Test Every Sink, Toilet, and Drain

This is where I roll up my sleeves (literally) and run some water. Every sink, every tub, every toilet—yes, even the jetted ones. The goal isn’t to check if the tile grout matches the backsplash. I’m here to see if water goes where it’s supposed to, how fast it drains, and whether there’s any hidden damage just waiting to show up.

Here’s How I Inspect Plumbing Fixtures

My standard walkthrough includes:

Running water at every sink – kitchen, bathrooms, laundry, utility.
Filling and draining tubs/showers – If accessible and safe to do so.
Flushing every toilet – Looking for slow fill, leaks, rocking bases.
Checking water flow and drainage – I check how long water takes to heat, flow rate at each fixture, and whether drains back up or gurgle.
Hose bib pressure test – I use a gauge to read static pressure from exterior faucets. Low pressure can point to supply line or valve issues.

What I’m Looking For—And What I’m Not

✅ I’m looking for: active leaks, signs of previous water damage, slow drains, low or uneven pressure, cross-connections, and visible pipe condition under sinks or near the water heater.
❌ I’m not looking to: inspect inside walls or underground lines, determine pipe sizing, or test water quality. That’s for licensed plumbers or environmental testers.

Video Documentation = Protection for Everyone

Every time I test a sink, toilet, tub, or shower, I’m filming it. This protects both the buyer and the seller. If something goes wrong later, there’s clear documentation showing that it was working—or not—on the day of the inspection. I also record how long it takes for hot water to arrive and how well fixtures drain.

This Comes Before Thermal Imaging for a Reason

All this water testing happens before I run the thermal scan. Why? Because thermal cameras are fantastic at spotting water leaks—but only if there’s moisture to detect. If I just turned on every fixture in the house, the camera may catch a hidden leak or damp spot that would otherwise go unnoticed.

Common Red Flags I See

Slow draining sinks – Often due to partial clogs or venting issues.
Wobbly toilets – A rocking base can mean a broken flange or past leak.
Under-sink corrosion – Especially on older copper or galvanized lines.
Pressure spikes – High pressure (above 80 PSI) can damage appliances or valves. I document it if found at the hose bib.

FAQs: Plumbing Function Testing

Do you test every fixture?

Yes. I operate all accessible sinks, tubs, showers, and toilets. I also check for functional drainage and pressure issues at each.

Do you test exterior plumbing?

Yes. I test exterior hose bibs for water flow and measure pressure with a gauge. Leaks or poor pressure are noted in the report.

Do you check for pipe leaks behind the wall?

No, but if I suspect a leak or see signs of one, I’ll use a thermal camera to investigate. I report anything suspicious for further review.

Can you tell if the pipes are up to code?

I don’t do code enforcement. I look at function, safety, and red flags. A licensed plumber should be called if installation quality is in question.

→ Next up: Post 22: Signs of Plumbing Trouble — What an Inspector Looks For

← Previously: Post 20: Water Heaters — What We Inspect (and What We Don’t)

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