The tiny house is moving forward in leaps and bounds, and then something comes up that stalls everything for a bit and then the build moves forward in a different direction until something comes up that has to be creatively encountered.    The plumbing demands of the house have certainly caused a few minor stalls, creative problem solving and multiple trips to the hardware store.

There are conversations in the tiny house community about the cost of a tiny house per square foot vs the cost of a traditional home.  I have strong opinions about that and won’t get into them now, but I will say that in a tiny house, particularly one in this climate, you have to fit in a lot of the same elements as a traditional home in a much smaller space and then fit in some things you would have to think about let alone find space for.

I started figuring out my plumbing needs and purchasing the big elements of my plumbing several months ago.  My plumbing system allows for pressurized water supply from a hose and also a supply via a  26 gallon fresh water tank under my kitchen sink.  The pressurized water is pretty straightforward – the water comes in and goes either directly to supply the taps of the kitchen sink, bathroom sink or bathtub with the normal bypass to the hot water heater OR it can fill the fresh water tank.  The fresh water tank can be filled 3 ways: (1) the pressurized supply that comes in through an RV water inlet that has a hose connection and  (2) a poured water supply line, (3) poured in through a marine water inlet in the counter.  Once the fresh water tank is filled, there is a water pump that draws water from the tank to supply cold water directly to the taps or to the hot water heater to supply hot water to the taps.    The reasons for the fresh water tank and the multiple ways of  filling it are weather related.  At -30 celsius, there is no guarantee that even the best heated potable water hose will be able to supply water to the house, and at the same time I want to be able to fill the water tank from inside – getting water into a small hole at chest height at -30 is not my idea of fun.

Once the supply aspect of the fresh water system was worked out and plumbed, the rest of the fresh water went really quickly.  The fresh water plumbing is done with pex and clear vinyl tubing (for filling the fresh water tank through the exterior and interior inlets).

The grey water has had its challenges as well.  The grey water from the bathtub, the kitchen and bathroom sinks all goes out of the house at the same spot under the tub.  The grey water will leave the house and go into a storage tank or a french drain will have to be set up, depending on the location of the house.  That system will work well until the weather goes below freezing.  I have no desire to chance what will happen in a grey water outlet or tank once the water in it freezes and expands.  Visions of cold hours under my trailer at -30  are also not my idea of fun.  The original plan was to have buckets under the sinks and to shower elsewhere in winter, both of which I am fine with.   Unfortunately, fitting a fresh water tank, a pump and a water heater under a counter does not leave any space for a bucket.

Here is the solution:  the grey water from the kitchen goes past the bathtub, joins up with the grey water from the bathroom sink and then heads to a valve that either sends it towards the tubs grey water and out of the house or to a grey water container inside the bathroom.  Putting the solution in place called for some creative plumbing and pieces.  I am still on the hunt for a 5-6 gallon  grey water tank that I will be able to remove from its spot in the bathroom and empty in a suitable location.

16 thoughts on “Plumbing”

  1. Something else you could also think about for keeping an outdoor tank of grey water from freezing is to use a stock tank heater. We use them all winter long (-20 F some nights) and they keep the animals water unfrozen. We’ve also had some success with a heating cable to keep barn water pipes thawed. Keep up the good work!

  2. We’re going to start building our tiny home this summer in Ontario (similar -30C climate). We are planning the same type of setup as you (hadn’t thought of the interior water inlet though). I am going to put an onboard grey water tank and probably have a pump that pulls the water towards it so it doesn’t have to be below the drains. Our design is for a 24′ trailer with a spot at the end for two 40g tanks (one freshwater, one greywater). I’m not sure if a drain pump might work for you but it might be worth a look. I was then planning on gravity draining from the greywater tank to smaller 7 gallon jugs for disposal.

    1. Hi! Just wondering how your plumbing has been working. I too am looking for a solution that allows me to have the greywater above the level of the shower drain (in the winter anyway). Thanks!

      1. My plumbing has been working really well. In the end, this winter, my grey water drained directly into the grey water bin I have underneath the trailer, the over flow froze next to it. I am very particular about what goes down my drain – all of the soaps I use are phosphate and sulphate free, etc.

    2. Hi Zach! Did you ever end up using the pumps for the greywater tank? How did that work out? I’m still trying to decide whether to set the greywater tank below the trailer frame and insulate thetank in a fancy way, or have the tank inside the envelop using pumps, or simply have it run outside. Sigh.

      Also, Natalie, did you end up using your greywater storage by your toilet? Did the water coming directly outside in the winter seem to work okay as a long term solution?



      1. Hey Jessie, sorry, we didn’t end up building the tiny house. Life took another turn and my wife needed to be closer to doctors/hospitals and the city. Hopefully some day. Best of luck with your plumbing.

      2. I did not end up using the greywater storage. The water coming directly outside in the winter seemed to work okay and wasn’t a problem in the spring. It probably helped that it was a slow thaw.

  3. Oh, I thought I’d mention, since you were looking for a 5-6 gallon grey water tank, if you go to a Canadian Tire or Walmart they have 7 gallon blue jugs (for freshwater) that would work perfectly.

  4. Good morning! I accidentally came across your blog this morning while looking for solutions to winterizing plumbing in a tiny house. Much to my surprise I came across your site. I’ve been spending all morning reading your posts. My wife and I are in the early planning stages of our tiny house and have some questions. I was wondering if there is a place I could email you? We live in Nova Scotia and were pleasantly surprised to see you were a former resident of PEI. I work for an airline and am often in Montreal. I would love to spend an afternoon visiting sometime if that’s possible. Thanks again for continuing to provide such awesome information during your build. BTW your house style is EXACTLY what we’ve been looking for. I would love to know where you bought the plans.

    1. Thank you for such a lovely comment. I have sent you an e-mail so that you can contact me when you are in town. I bought my plans from Tumbleweed. I built a modified Cypress.

  5. Hey, I am currently building my house and the problem I am running into is the venting. I haven’t seen many people vent their drainage but all forums seem to make an issue out of it. I didn’t know if these principles applied to systems with tanks vs. city.

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