Understanding how the plumbing works in a Tiny House can help you fix any problems that arise in the future.
Bringing water into the Tiny House
Every Aussie Tiny House comes with a regular tap fitting for connecting to mains water. However, most of our clients have a water tank and collect rainwater from the roof via downpipes. It makes ecological and economical sense, and the plumbing system is relatively simple. It’s not uncommon for a standard suburban home to have a rainwater tank nowadays!
Grey water leaving the house
Grey water is the wastewater from the shower, bathroom and kitchen sink, and washing machine. As it leaves the house, greywater passes through a filter and a grease trap before running through a gravel pit outside and onto the garden. Grey water should not be released into lakes, creeks, or oceans because it can pollute them. Check the Australian Tiny House Association for area-specific local council regulations.
What’s black water?
Black water is sewerage from the toilet containing faecal matter and urine. A composting toilet eliminates the need for a qualified plumber and council permits to connect to sewage and septic tank wastewater removal. Local councils have individual regulations for the disposal of black water.
Mapping out the plumbing lines for a Tiny House
Social media often shows Tiny Houses on the move with location-free owners carting bottles of water to use in gravity-fed showers or for doing the dishes. That’s a caravan lifestyle and a house without plumbing! Vanlifers regularly use dump stations for grey and black water and fill their onboard tanks at water fill stations.
Whether you’re building your own Tiny House on wheels or having it built for you, a water tank is a great idea for most Australian locations. A rainwater collecting and storing tank, with a pump to circulate and pressurize the water, provides a fully functioning house and the freedom of living off the grid.
Although water pumps can be noisy as they whirr when in use, because Tiny Houses are small they don’t need any long runs of PVC piping. When designed right, the plumbing can be relatively easy to lay and maintain and the chance of clunking from air getting in the pipes is reduced. Yep, we all know that sound!
Much like a traditional house, water supply comes into the Tiny House and usually forks, with one line to the hot water heater and the other directly to the sinks, shower and washing machine. The line coming out of the hot water heater will then be your hot supply to your sinks, shower and washing machine. Grey water exits the house via the drain lines from all of these areas, typically converging into a main drain line.
Heating the water
The reliable tankless Rinnai gas hot water system we use as standard on Aussie Tiny Houses delivers hot water as you use it. Cold water runs over the heated cell exchanger as it passes through the unit, so you’re not heating water when you’re not using it. You won’t ever run out of hot water! The Rinnai system avoids the need to store water in a heavy tank and keep it warm.
When planning the plumbing for your Tiny House, consider the washing machine and whether it takes in hot water or heats cold water itself. Every Aussie Tiny House is built plumbed ready with hot and cold taps for the washing machine.
Draining the grey water
For a self build, it can be simpler having the sink and shower on the same side of the house. This can help in planning venting for the plumbing system and without it your drain lines won’t drain properly. Our designers’ tip is to map out your entire plumbing system. You don’t want to install a shower drain only to discover there’s a trailer beam right below it!
Drain pipelines need to be sloped in a very specific way. Too shallow a slope and water might clog, too steep and the solids won’t drain! If your Tiny House isn’t level, you’ll notice water won’t drain down the sink very well.
Tank water can be either pumped into the house or gravity fed if the tank sits higher than the house. The question then becomes…how will the rainwater be piped into the tank? I did want to let you know this was an option but honestly most of our clients simply harvest water off the roof and pump it into the house.
Maintaining a good working plumbing system
It’s important to have a whole house shut off system, the mains tap if it was an ongrid set up! You’ll want this if you go away for a while or need to service the plumbing system. Make sure you always have access to the water lines if you need to fix any problems that arise.
It’s good to do periodic checks of the plumbing when you’re doing a monthly check on your trailer level. Clean your system of soap scum, hair, and other debris and check the physical components (eg: pumps, filters, pipe junctions) for leaks and damage.
Take frost prevention seriously to avoid damage to your pipes. If you’re building your own Tiny House, take a tip from our tradies and wherever possible keep your body lines on the inside of the envelope. This means run the main plumb lines within the interior wall cavity. For any exterior piping from the connection from your water source to your Tiny House, insulate and use heat tape. Pipes can also be buried in the ground but remember to draw a map of where you laid them for when that time comes to find a mysterious leak!
It’s important to use biodegradable cleaning and beauty products that are perfectly safe to go back into the environment when the grey water is used for watering your garden.
Do you have a Tiny House plumbing tip to share with the ATH Community or a question for our Sales Development Representatives? Comment below, we’d love to hear from you.
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