So you just finished all the sweat and swear words installing plumbing in your tiny house. Now comes the moment of truth: the plumbing inspection. If you’re anything like me when I started, you’re probably imagining the inspector showing up with a checklist longer than your build timeline and a magnifying glass to find every single screw-up.
Here’s the deal. Tiny house plumbing inspections aren’t some mythical beast. They follow rules, but they’re not out to ruin your day. Knowing what inspectors look for can save you a ton of stress, money, and time. I’ve done over 200 tiny house builds, so trust me when I say I’ve seen both the good and the painfully ugly.
What’s on the Plumbing Inspection Checklist?
First off, every jurisdiction is a little different. But most inspectors want to see a few core things. Think of it as the “plumbing basics 101” for tiny homes.
1. Proper Venting
You have to vent your drains or you’ll have water that drains slower than molasses on a cold day. Plus, no vents means sewer gases could sneak back into your tiny home. Yeah, that’s a no-go. Inspectors check that all your vents are the right size and go through the roof or an approved vent location.
For example, your 1.5-inch vent pipe needs to be clear of obstructions and connected correctly. I once had a client who forgot to install a vent on the shower drain. The inspector caught it, and that fix cost him an extra $150 and a few days of frustration.
2. Pipe Slope and Drainage
Drain pipes can’t just be tossed in willy-nilly. They need to slope downward at a specific angle—usually 1/4 inch per foot. Too flat and water pools. Too steep and solids might not flush properly. The inspector will measure this slope. Don’t guess here. Get a cheap line level from Home Depot ($12) and check before you cover anything up.
3. Pipe Materials and Connections
Yep, they check your pipes. CPVC, PEX, copper, or ABS - the inspector wants to see approved materials. Plus, they want clean connections. No leaks, no goofy fittings, no tape where there shouldn’t be tape. For DIYers, PEX is a lifesaver because it’s flexible and pretty forgiving, but don’t cheap out on connectors. A $47 crimper from Lowe’s is a better investment than constant repairs.
4. Water Supply and Shutoff Valves
Your tiny house has to have a main water shutoff valve. Sounds obvious but you’d be surprised how many people forget this. It needs to be accessible, not jammed behind a wall or under a pile of lumber. Inspectors will turn this valve to check if it works. So test it yourself first!
5. Backflow Prevention
This one’s serious. If your water supply connects to a well or a city line, inspectors want to ensure no chance of contamination. This means installing a backflow prevention device. I installed one on a tiny home last winter that cost $85 from a local plumbing supply. Worth every penny.
6. Hot Water Systems
Tankless, electric, propane - whatever you chose, the inspector will verify it’s installed safely. Gas lines need proper venting and shutoff valves, electrical connections must be up to code, and the system has to have temperature controls to avoid burns.
7. Fixture Installation
They check sinks, toilets, showers. Are they securely fastened? Do they drain properly? No leaks? Oddly enough, I’ve seen clients try to save a few bucks by installing RV toilets in tiny houses. Real talk: RV toilets suck for tiny homes. They’re noisy, can clog easily, and the water seals often fail. You’ll pass inspection with a proper composting toilet or low-flow residential model, and you’ll thank yourself later.
8. Gray Water and Waste Systems
If you’re off-grid or trying a gray water setup, inspectors want to see that your system doesn’t pollute. That means filters, soak beds, or approved storage tanks. In some places, gray water disposal has strict rules. I had a build where gray water was discharged into a dry well, and the inspector made me install extra filtration at a cost of $200. Annoying but necessary.
9. Winterization Measures
If you’re in a cold climate, inspectors want to see proof your pipes won’t freeze. Insulation, heat tape (which can run $30-40 per 50 feet), and proper placement in heated areas are typical requirements. One client learned this the hard way when a pipe froze and burst last January. That $1,200 repair could’ve been avoided with heat tape and insulation.
Inspector Requirements Plumbing: What Qualifies Them?
Not every inspector is a plumbing pro, but they have to meet state or local licensing requirements. Usually, they’re either certified plumbers or building inspectors with plumbing training. Some towns have specific tiny house inspectors. If you’re lucky, your inspector has installed a tiny house or two and won’t freak out over stuff like 12-volt water pumps or composting toilets.
Look, inspectors aren’t trying to fail you for fun. They want to make sure your plumbing is safe, sanitary, and won’t flood or poison your home. If an inspector is being unreasonable, don’t hesitate to ask for their standards or call the local building department. Sometimes it’s just a communication issue.
Pass Inspection Tiny Home: Tips From Someone Who’s Been There
Here’s the reality: tiny house plumbing inspections can be nerve-wracking but totally doable if you prepare.
- Document everything. Take pictures during installation. Keep receipts of materials and products. Don’t cover pipes or walls before a rough-in inspection. That’s when they check your pipes before drywall or paneling. Test everything. Turn on taps, run showers, flush toilets. Fix leaks before the inspector arrives. Know your code. Local codes can be found online or at your city hall. Read up on them. Invest in quality tools. A $47 crimper, a $12 line level, and some pipe wrenches go a long way. Don’t be afraid to DIY, but call a pro if you hit a wall. I once tried to install a gas water heater alone. Let’s just say, the pro fixed my mess in 30 minutes.
DIY Installation Guides and Cost-Saving Tips
DIY plumbing in tiny houses saves thousands, but it’s not all rainbows. For instance, PEX piping runs about $0.50 per foot at Home Depot. A standard 50-foot roll costs around $25. Copper costs three times that. A $47 crimper might seem steep but it’ll last years.
Composting toilets? Don’t be scared. I was too at first. Turns out, they don’t smell if you follow directions. I recommend Nature’s Head or Sun-Mar models. They run from $1,000 to $1,500, which sounds pricey but beats plumbing and septic hookups.
Winterization isn’t just about insulation. Heat tape around exposed pipes is a lifesaver. It costs about $35 per 50 feet. You can also install pipe insulation sleeves for $0.50 per foot. Planning ahead saves cold nights and busted pipes.
Off-Grid Systems and Gray Water Management
Off-grid setups require extra planning. If you’re running a cistern, you need a good filtration system. I’ve installed tiny houses with three-stage filtration (sediment, carbon, UV) for about $400 total.
Gray water management can be tricky. Neighborhoods get picky about where you discharge water. In one build, the inspector required installing a gray water pump system that cost $300 plus labor. If you want to DIY, consider a gravity-fed system with a soak bed or drip irrigation for plants.
Troubleshooting Common Problems
Leaks are the biggest headache. Even the best DIYers miss a loose fitting now and then. I suggest pressure testing your system with a $25 air compressor gauge before closing walls.
Slow drains usually mean bad slope or clogged vents. Fix the slope or add a vent stack.
Frozen pipes? Heat tape and insulation fixes 95% of cases.
Smelly drains? Venting or a P-trap problem. Adding or fixing traps usually clears that up.
Honest Product Reviews From the Trenches
PEX Piping: Flexible, easy to install, and cheap. Buy the crimper. Don’t cheap out on fittings.
Composting Toilets: No smell, easy to maintain, pricey upfront but no water bill. Nature’s Head is my go-to.
RV Toilets: Don’t bother. They clog and leak.
Heat Tape: Saves your pipes. Buy from trusted brands. Don’t skimp.
Tankless Water Heaters: Great space saver but tricky to install. Call a pro if you’re not confident with gas lines.
Final Thoughts
Tiny house plumbing inspection doesn’t have to be a horror story. If you follow the basics, document well, and test like crazy, you’ll pass inspection tiny home style. Look, plumbing’s not glamorous but it’s the backbone of your tiny living comfort.
And remember, the $150-200 you save by DIYing your plumbing can go straight to that sweet tiny house deck or a killer composting toilet upgrade.
FAQ
What does a tiny house plumbing inspection include?
The inspector checks pipe materials, venting, water supply and shutoff valves, drainage slope, fixture installation, backflow prevention, hot water systems, gray water management, and winterization measures.
How do I pass a plumbing inspection in my tiny home?
Follow local codes, install proper venting, slope your pipes correctly, use approved materials, test everything for leaks, and keep your shutoff valves accessible. Document https://www.tinyhouseplans.com/blogs/guides/do-tiny-homes-have-plumbing your work and don’t cover pipes before rough-in inspections.
Are composting toilets allowed for tiny house plumbing inspections?
Usually yes, if installed per manufacturer instructions. Make sure your local codes approve them. Composting toilets often pass better than RV-style toilets.
What tools do I need for DIY tiny house plumbing?
A $47 PEX crimper, a $12 line level, pipe wrenches, Teflon tape, and decent pipe cutters are basics. Heat tape and insulation are necessary for cold climates.
How much does plumbing inspection cost for tiny houses?
Costs vary by location but expect $100 to $300. Some inspectors charge by the hour, others have flat fees. Check your local building department for specifics.
Can I do my own plumbing inspection?
You can pre-inspect your work but official inspections must be done by licensed inspectors or plumbers to pass code and get permits.
What common mistakes cause plumbing inspection failures?
Missing vents, poor pipe slope, inaccessible shutoffs, unapproved materials, leaks, lack of backflow prevention, and improper fixture installation are the top culprits.
How do I winterize my tiny house plumbing?
Use pipe insulation sleeves, install heat tape on exposed pipes, drain water lines if unused, and keep interior temperatures above freezing.
Is PEX piping good for tiny houses?
Yes. It’s flexible, affordable, and easier to install than copper. Just buy good connectors and tools.
Do I need a backflow prevention device?
If your water supply connects to a public or private source, yes. It prevents contamination and is usually required by inspectors.