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Tiny House Plumbing


Plumbing is probably one of the scariest parts of any build, especially when you have zero construction experience (like me). I’ll take you through my Tiny House plumbing, but keep in mind that there are several ways to do this depending on your preferences.

One thing to note before we get started: my set up is simple. I only have one shower and one sink. I do not have a washing machine, dishwasher or bathroom sink. My toilet is a waterless compost toilet.  My system is set up to be on-grid or off-grid and to be water conscious.

Watch THIS VIDEO for a Detailed Look at my Tiny House Plumbing:


Alright, are you ready? Let’s dive into Tiny House Plumbing!

To understand this article, you’ll need to learn the following terms: off-grid, on-grid, fresh water, greywater, and black water. Don’t worry, I’ve defined them all below.

“Off-Grid” VS. “On-Grid”

What do these terms mean? Off-grid means that you are NOT connected to city water and that your system is self-contained. You might be off-grid when dry camping or parked on a  piece of land without city connections. On-grid is when you are connected to city water, such as in an RV park.

I have both off-grid and on-grid options in my tiny house, which I recommend for flexibility in parking. Of course, if you will always have a city water connection, having an off-grid system is not necessary. First, let’s discuss freshwater for both off-grid and on-grid. 

Freshwater is the water you use for drinking, cooking, showering, toilet, washing dishes, etc. 

freshwater tank

My “Off-Grid” freshwater system

First, let’s talk about my off-grid fresh water system. For water storage, I fill a 46-gallon water tank, which is secured under my kitchen counter. I fill this tank by connecting an RV drinking hose (or carrying jugs of water) to my water inlet.

The average American uses between 80 -100 gallons of water a day, so it’s good I am not “average.” I use about 10 gallons of water a day. When I am off-grid, I fill my tank every 4 days.

Water Inlet
My Water Inlet

Now that we’ve gotten water into the house, how does it work?

To heat the water, I have a tankless propane water heater, which is extremely efficient. Read more about it here. For off-grid water pressure, I use a water pump. The water pump runs on 12V and the water heater requires 12V to spark and to protect itself from freezing. My house is wired for 110, so I have a 12V converter to run these appliances. These elements can easily be powered by a gas generator or solar power when off-grid.

Water Heater

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My “On-Grid” freshwater system

When I am “on-grid” (connected to city water) I simply connect my RV drinking hose to the supplied spigot and there’s no need to use my water tank or pump. In the winter, I need to use a heated hose and insulated spigot. More on Tiny House winterization here.

heated water hose
My Freshwater Heater Hose (for Winter)


Once the city water pressure was so strong it actually broke my inlet! Since then I’ve replaced my inlet’s plastic fittings with brass ones, and I’ve purchased a pressure regulator.

The plumbing choice for tiny homes is PEX. It’s DIY friendly and lightweight. You will need the PEX piping,  crimping tool, brass elbows and fittings to do the jump yourself.

As a note, I also use a low-flow shower head to conserve water. I have not found this to be a problem when washing my hair. I’ll also mention that the water pump I initially bought (pictured below) can be a bit loud. I ended up replacing it with this more expensive and quieter water pump. Both work fine, but if you want the quieter version, go with the one I just mentioned.

Greywater is the water that drains out of sinks and showers

Tiny House Plumbing
My Sewer Hose

Greywater is not necessarily waste. I use biodegradable products for my soaps, shampoo, conditioner, lotions, etc. My greywater consists of these soaps, my body oils, and food products diluted with fresh water. If I had my own land, I would create a drainage system to use my greywater for irrigating my garden, similar to Art’s tiny house system. It’s a great way to recycle!

When I’m off-grid, I use a portable greywater tank. If I’m on-grid, usually at a campground, I connect to the sewer system with an RV sewer hose.

Tiny House Plumbing
Portable greywater tank

As with fresh water tanks, greywater tanks come in all shapes and sizes. Mine is only 15 gallons, so I have to dump it once a day. I’m actually glad it’s small because I can empty it myself (it weighs almost 100 pounds when full).

How to dispose of greywater when Off-grid

Where I dump my greywater really depends on my location. If I’m on at a national park, I dump it at the allocated dump stations. Dump stations are also sometimes available at rest stops. If I’m in a residential neighborhood, I dump my greywater in the nearest sewer drain or I ask my host if I can use it to water their grass. If it’s raining outside, that’s a good time to dump! Any smelly food product is easily washed away by the rain. Consider it this way, most people wash their cars in their driveway. The soaps they are using have chemicals that are substantially more harmful than my greywater.

*As a note, dumping greywater is not legal everywhere. Research your location and use your best judgment. 

Greywater drain and portable tank

Black Water is the wastewater from a toilet

I don’t have this because I use a composting toiletNo, it doesn’t stink. Read my full review.

I did plumb a freshwater line for a possible flush toilet addition in the future (in case I sell my house one day). You can see that above my toilet in the below photo.

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Dumping black water

This is a very unenjoyable process. You will need to install a black water tank on your tiny house, and then pay to have it pumped out or drive it to a dump station and do it yourself. You can also bypass your black water tank and connect to the sewer via an RV sewer hose. 

Guess how you know when it’s time to dump? Smell…

I’m told that the average full-time RVer has to dump their black water every two weeks. I dump the solids in my composting toilet every 3-4 months. I don’t have much more to say about black water because I don’t have it. My suggestion is to go waterless with a compost toilet. 

Additional Tiny House Plumbing Resource:

Here is a diagram of a more complicated Tiny House plumbing system with two sinks and a black water tank.

Tiny House Plumbing

Other Tiny House Resources:

YOUR TURN: How did you handle Tiny House Plumbing?



  1. Robert Baptista
    August 8, 2019 / 3:27 pm

    With a composting toilet, where do you dump your “liquids”? Go in to McDonalds restroom and pour?

    I wish I had a tiny home, but I’d need a second trailer that was basically a closet. I watch a couple of tiny house build shows that seem like they build someone a house and they are screwed after that. They rarely mention any details other than a fresh water tank or composting toilet, but they will build someone a house and they tow it off into the mountains and say “there ya go”. There’s no fresh water tap, there’s no gray or black water tanks or septic system. They drop them off in the middle of some “friends” horse field or in a meadow in the mountains. Being a practical jerk that I am, I immediately see this as a “honeypot truck” comes every day, a fresh water delivery every day, two solar panels won’t run their TV, microwave, dishwasher and close washer unless they do each once a week. The people who want to “travel” with their house, may stay in KOA campgrounds if available, but it really seems that many of these builds and situations, like 5 people in one tiny home, off grid, just isn’t practical.

    I guess I wish their shows were longer, so they could address these issues for each of the umpteen different combinations of builds they do, which would help people figure out what kinds of capacities, hookups, travel plans, “friend squatting”, etc needs and how to accomplish filling those needs.

    • August 17, 2019 / 9:39 am

      I dump outside. Dilute with water, and use it to water the trees. It’s basically like peeing outside. You can also pour it down a drain into a sewer if you have access to that.

  2. January 21, 2018 / 9:52 pm

    is there a way to go completely off grid… i mean where you have a water filtration system so that you dont have to keep refilling your fresh water tank…

  3. Grace
    June 1, 2017 / 2:48 pm

    What do you do with your gray water tank when on the road? Do you just throw it in the back of the truck or do you have it secured to the bottom of the trailer somehow?

      • snu
        June 25, 2017 / 6:02 pm

        Hello there,
        thank you deepbottomheartedly for sharing the details of your plumbing set-up!! so much appreciated (me also noo building experience:D). You say, that when you are on grid you connect a hose to a supplied spigot – would that be a different inlet than for the H2O-tank or is there a different way how you skirt your tank and pump when on the grid?
        also, i am wondering how you fill the tank when carrying water – do you use a funnel?

      • June 27, 2017 / 10:38 am

        There is a different inlet hole for the tank and simply connecting to city power. If look at the photo of the inlet, you will see two holes – one for the tank and one for bypassing the tank/pump and simply using city water and pressure. You can fill the tank by connecting to a hose or carrying jugs with a funnel. Hope this is helpful.

  4. raphaelberrios
    May 10, 2017 / 8:50 pm

    Although it relates more to your electrical system, how did you wire the 12v converter? It looks as though you have run standard romex to the AC supply end of the converter. Is that just running to a breaker in your AC panel? I am in the process of trying to set up a similar system and having trouble finding information on how to safely get it all wired. Thanks

    • May 12, 2017 / 9:34 am

      I’m sorry, but I don’t really remember. Also, Guillaume did this, with maybe some help from our electrician. I think it’s pretty straight forward, but I can’t answer this question.

      • Ben w
        July 27, 2017 / 5:52 am

        A D.C. Converter is just a power supply, much like a phone charger on a bigger scale. Run ac to the inlet side terminals- from a breaker or another circuit, and you’ll have D.C. Available on the outgoing terminals to wire to your D.C. Items. It’s all labeled and super easy to do.

      • July 27, 2017 / 8:34 pm

        I would say yes they ran it to the panel off a 20a breaker to run it when hooked up to on grid supply. The inrush current on the Amazon listing says 25 amps which makes me as an electrician nervous. I’d like to see a number 10 awg wire feeding the inverter to make up for the inrush amps not to smoke the wire powering the inverter.

  5. February 16, 2017 / 8:45 am

    Where did you get your tub? I’m looking for something similar.

  6. Alexis
    November 28, 2016 / 1:49 pm

    Hello! How did you attach the grey water tank to the bottom of your house? I’m building an expedition vehicle and am having trouble finding a company that can recommend a product designed to be attached to the underside of the vehicle. Thank you

    • November 29, 2016 / 8:51 am

      Also, note that the portable grey water tank is not attached to the trailer. It’s on wheels so that it can be towed away and dumped easily. If you are looking to attach a tank to the underside of your vehicle, check out RV forums for their recommendations.

    • February 11, 2017 / 3:40 pm

      Hi! I didn’t attach it. I have a rolling, portable greywater tank. When I move around I simply throw the tank in the back of my truck. I think it is better this way because if the greywater tank was attached, I would have to drive my tiny house to the dumping station every time I wanted to dump it. I’d rather disconnect the greywater tank and roll it to the dump station.

      • Mary Gregory
        January 21, 2020 / 6:56 am

        Hey! Do you only have the portable grey water tank that is set up directly to your shower/sink waste, or do you have a collection grey tank in the house, that then dumps into either the sewer line or the portable one to drag off waste water?

      • January 21, 2020 / 8:12 am

        I only have a portable greywater tank. The sink and shower both have pipes that come to a T, and then connect to the portable greywater tank.

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