Tiny House Plumbing: The Complete Step-by-Step Guide

Water is an essential need in buildings, including residential buildings. Hence you need to do the plumbing needs on any house, including tiny houses. You can move tiny houses on wheels from one location to another. Every home needs a water supply and piping for sewage and other liquid waste disposals. Plumbing creates the channels through which water supplies tiny houses. Plumbers also use it to disposes of wastes. Plumbing a tiny home can be a challenging but rewarding task. In this guide, you’ll learn about tiny house plumbing from the questions we will answer. Some of the questions this guide will cover  include the following:

How Does Tiny House Plumbing Work?

Tiny houses are small, portable, and often off-grid, often 400 to 500 square feet. Because of their size, they often design tiny houses in small spaces with utilities such as water and sewage. Architects design tiny houses’ plumbing systems to be compact, efficient, and self-sufficient. Tiny houses generally have smaller and simpler plumbing systems compared to traditional houses. Here are some ways that tiny house plumbing systems often work:

Water Supply: Tiny houses often have a small water tank that stores a limited amount of water. The usual location for the water tank is either on the side of the house or underground. Contractors connect it to the plumbing system with pipes.

Waste Water Management: Tiny houses often have a small holding tank for wastewater from sinks, showers, and toilets. Store the wastewater in the tank until you can dispose of it. Other tiny houses may use a standard bathroom connected to a septic or municipal sewage system.

Gray Water Management: Use gray water for purposes other than toilet waste, such as water from sinks and showers. In a tiny house, collect gray water in a separate tank and use it for irrigation or other non-potable purposes.

Tiny House Plumbing Diagram

A Tiny House plumbing diagram is a visual representation of the plumbing system. It often includes the locations of the various:

• Pipes
• Fixtures
• Appliances

that make up the system and the connections between them.

The plumbing system in a Tiny House often consists of a:

• Water supply system
• Drainage system,
• Sewage system

The water supply system includes the:

• Water source (such as a well or city water)
• Water meter
• Pipes that deliver water

to the fixtures and appliances in the home

The drainage system consists of the lines that carry used water and waste away from the fixtures and devices. The sewage system includes pipes transporting sewage waste to a septic tank or municipal sewage treatment plant.

In a Tiny House the plumbing diagram is often represented by the:

• Water Supply system by the Blue lines
• Drainage system by black lines
• Sewage system by green lines

The diagram shows the various fixtures and appliances. Among these fixtures, we can list the following:

• Sinks
• Toilets
• Showers

It shows their locations in the home.

It is vital to have a detailed and accurate Tiny House plumbing diagram. It can help homeowners and contractors understand the layout of the plumbing system. It also helps to identify any issues or problems that may arise.

Tiny House Plumbing Options

You can deploy several plumbing options and types. The best plumbing option for a tiny house will depend on the specific needs and constraints of the house. Yet, there are two main category plumbing options suitable for tiny homes, including

• On-Grid tiny house plumbing
• Off-Grid tiny house plumbing

Tiny Houses on wheel grid plumbing on-Grid plumbing

In a tiny house’s on-grid plumbing system, you connect the plumbing to the utility system for water and sewage lines. It allows the tiny house access 24/7 to running water, a toilet, and other plumbing fixtures.

The plumbing in a tiny house on-grid system is often smaller in scale than that of a traditional home. It is due to the smaller size of the tiny house. It is also crucial to plan the plumbing layout in advance in the tiny house, as space is often limited. One advantage of an on-grid plumbing system in a tiny house is that it allows for a more convenient and comfortable living experience. It provides access to running water and proper sewage disposal.

It is important to note that an on-grid plumbing system in a tiny house may be less expensive to install and maintain. But, you don’t always have the option to connect to the utility. For the off-grid system, you will need to invest in renewable technologies, such as:

• For water, you will need to get water from an underground well
• For swaage, you will need to install a septic tank system
• For power, you will need to install a solar system
• For cooking gas, you will need to use propane gas tanks
• For internet, you will need to connect to an independent provider like Starlink

as it requires a connection to the main water and sewage lines.

It is also relevant to consider local building codes and regulations when installing an on-grid plumbing system. These codes vary by location.

Tiny House Plumbing Off-Grid Plumbing

Tiny house off-grid plumbing in a tiny house has to do with a system not connected to a municipal utility water or sewage treatment system. It also refers to an electrical system not connected to an utility power system.

It means the tiny house must be self-sufficient for its water, waste and electrical needs. Off-grid tiny houses often use alternative or renewable sources for water. These alternatives include rainwater catchment or a well. It may also use alternative waste management systems, such as composting toilets or septic systems. Architects design the plumbing system in an off-grid tiny house to use and recycle water. It must also treat and dispose of waste in an environmental responsible manner.

The most common type of off-grid plumbing system for a tiny house is a combination of water catchment, filtration, and storage. Water catchment involves collecting rainwater from the roof or other surfaces. Then it directs it into a cistern or storage tank. This system filters water to remove any impurities or contaminants before using it for drinking, cooking, or bathing.

Besides, a water catchment and filtration system, tiny houses may also include a greywater system. Its goal is to recycle used water from sinks, showers, and washing machines for irrigation or other non-potable uses.

How to Plumb a Tiny House On Wheels

Plumbing a tiny house on wheels (THOW) requires skills, careful planning, and attention to detail. The system must be safe, functional, and compliant with local building codes. Plumbing a tiny house on wheels takes one or two days to complete. Here are some steps you can follow to plumb your tiny house on wheels:

Design your plumbing system

Start by sketching out the layout of your THOW. Determine where you will locate the plumbing fixtures and appliances. Consider factors such as the:

• Location of your water and waste lines
• Size of the pipes you will need
• Type of water heater you need

Choose your plumbing materials

Select materials suitable for use in a THOW, such as PEX tubing, which is flexible and easy to install. Avoid goods prone to freezing, such as PVC, as you may live with your THOW in a freezing temperatures area during the winter.

Install the water supply lines

Run the water supply lines from the point of connection to your THOW (e.g., a city water connection or a well). The water lines conect to the locations of your plumbing fixtures and appliances. Use correct-sized pipes and fittings, and ensure to use pipe insulation to prevent freezing.

Install the drain, waste, and vent system

The Drain Waste Vent – DWV – system consists of pipes that carry:

• Wastewater
• Sewage

away from your THOW and vent pipes that allow air to flow in and out of the system to prevent blockages. Be sure to size the lines and use appropriate fittings to ensure the proper functioning of the plumbing system.

Tiny House Plumbing Basics

The basics to consider during the plumbing of tiny houses in two stages are: rough-in plumbing and finish plumbing.

Rough-in plumbing refers to installing the:

• Pipes
• Valves
• Fixtures

hidden behind walls, under floors, or ceilings. This often includes the main water supply lines, drainage, and venting systems.

Finish plumbing refers to installing the pipes, fixtures, and appliances that are visible and accessible in the house. It includes sinks, toilets, showers, and water heaters. A licensed plumber should do rough and finish plumbing, working with pipes that carry water and sewage. It can turn into a dangerous situation if you don’t do it the right way.

Tiny House Rough-in Plumbing

Rough-in plumbing includes installing the pipes and other components hidden behind a building’s:

• Walls
• Floors
• Ceilings

In a tiny house, rough-in plumbing may involve installing pipes for the:

• Water supply
• Waste systems
• Gas lines

if the tiny house has gas-powered appliances.

Plumbers complete the rough-in plumbing before they complete the finish plumbing. They install fixtures and interior devices. The water supply rough in plumbing requires 1/2 PEX which is adequate. You can also use the larger 3/4 PEX pipes for the tiny home’s pool. But many tiny homes often use the 1/2 PEX because it is affordable, quite durable, and easy to fix, use and install.

Install Tiny house Water inlet

Installing a water inlet for a tiny house can be quite straightforward. Still, it’s crucial to follow the instructions for your particular inlet. Ensure that you have all the necessary tools and materials. Here are some general steps to follow:

• Choose a location for the water inlet that is easy accessible. It is best if you install it on an exterior wall of the tiny house. Ensure the place is near a water source, such as a hose bib or a water line.
• Cut an opening in the wall for the water inlet using a hole saw or jigsaw. The opening size will depend on the specific inlet you are using.
• Install a mounting plate for the water inlet on the tiny house’s exterior. It will often involve drilling holes and using screws to secure the plate to the wall.
• From the inside of the tiny house, attach the water inlet to the mounting plate using the screws and other hardware provided with the inlet.
• Connect the water supply line to the inlet using a hose or pipe as necessary. Use the appropriate fittings and connectors for your specific inlet and water supply line.
• Test the water inlet to ensure that it is functioning and that there are no leaks

Polar White City Water Flange

Polar White City Water Flange is a plumbing fitting that connects the water supply line to the city water inlet on a tiny house on wheels. Here are the steps for using the Polar White City Water Flange:

• Locate the city water inlet on your tiny house. This is usually located near the front of the house and is often a 3/4″ threaded fitting.
• Attach the Polar White City Water Flange to the city water inlet using the supplied mounting hardware. Make sure the flange is secure and tightened to the appropriate torque.
• Connect the water supply line to the flange. The water supply line is often a flexible hose with a 3/4″ fitting on one end that connects to the flange.
• Turn on the water supply and check for any leaks. If there are any leaks, tighten the fittings or replace damaged parts as necessary.
• Once the water supply is secure and there are no leaks, you can use the water in your tiny house as needed.

Install a Water Pressure Gauge

Installing a water pressure gauge on a tiny house on wheels is a simple process. It can help you track and maintain the proper water pressure in your plumbing system. Here are the steps for installing a water pressure gauge:

• Locate a suitable location for the water pressure gauge. The gauge should be visible and accessible but not be in a location where it is subject to extreme temperatures or vibration.
• Shut off the water supply to the tiny house. This will prevent water from flowing through the system while installing the gauge.
• Locate the main water supply line for the tiny house. This is often a 3/4″ pipe that supplies water to the entire house.
• Cut a small section out of the main water supply line using a PEX cutter. Make sure the cut is straight and clean.
• Install the water pressure gauge on the main water supply line. Attach the meter to one side of the cut pipe and connect the other side to the gauge using a threaded fitting. Make sure to secure the indicator fastened and tightened to the appropriate torque.
• Turn the water supply back on and check the gauge to ensure proper installation. The gauge should read the current water pressure in the system.

Install a Supply plumbing manifold

Installing a supply plumbing manifold is a valuable way to centralize water distribution. Manifolds help also to prevent future freezing while providing easy access to supply pipes. Here are the general steps for installing a supply plumbing manifold:

• Determine the location of the manifold. It should have easy access for maintenance near the main water supply line.
• Cut the main water supply line and attach the manifold using fittings and pipe glue. Be sure to follow local plumbing codes and use the proper fittings for the type of pipe you use.
• Install shut-off valves on each branch of the manifold. It will allow you to control water flow to each branch.
• Attach the supply lines to each manifold branch using fittings and pipe glue. These lines will run to the various fixtures and appliances in the building.
• Test the manifold by turning on the main water supply and checking for leaks.

Install PEX Lines

PEX, or cross-linked polyethylene, is a type of flexible plastic piping. It is often used for plumbing in residential and commercial buildings. It is a popular choice for tiny homes because it is:

• Lightweight
• Easy to install
• Resistant to freezing and bursting

To install PEX lines in a tiny house, you will need the following tools and materials:

• PEX Tubing: Use this flexible plastic piping to carry water to and from your fixtures
• PEX Fittings: Use these to join PEX tubing lengths together. Then connect the tubing to fixtures
• Crimping Tool: Use this tool to secure PEX fittings onto the tubing
• Pipe Cutter: Use this tool to cut the PEX tubing to the desired length
• Pipe-Cutting Jig: It helps you make straight, precise cuts for cutting PEX tubing

PEX, or cross-linked polyethylene, is a type of plastic piping used for water supply and drainage systems. You can use it in residential and commercial buildings. If you are looking to install PEX lines in your home or business, here are some steps you can follow:

Determine the Layout of the PEX Lines

Before installing the PEX lines, you need to plan the route the pipes will take. Consider factors such as the:

• Location of the water heater
• Distance from the water source
• Location of the fixtures (e.g., sinks, showers, etc.)

you will connect to the PEX lines.

Gather the Necessary Tools and Materials

You will need various tools and materials to install PEX lines, including a:

• Pipe cutter
• Pipe-bending tool
• PEX crimp tool
• PEX rings
• PEX tubing

Cut and Bend The PEX Tubing

Use the pipe cutter to cut the PEX tubing to the correct length. Use the pipe-bending tool to bend the tubing into the shape you need.

Attach the PEX Fittings

Use the PEX crimp tool to attach the PEX fittings to the PEX tubing. Make sure to secure the fittings to prevent leaks.

Connect The PEX Lines to The Fixtures

Once you have installed the PEX lines and fittings, you can connect them to the fixtures (e.g., sinks, showers, etc.) in your home.

Insulate PEX Lines

Insulating PEX lines can help to prevent heat loss, reduce energy consumption, and prevent freezing in cold weather. Here are a few steps you can follow to insulate your PEX lines:

• Measure the length of the PEX lines you will need to insulate. This will help you determine how much insulation you will need.
• Choose an appropriate type of insulation. Use several insulation materials on PEX lines, including:
• Foam tubing
• Fiberglass wrap
• Pre-slit foam pipe insulation
• Cut the insulation to the appropriate length. Measure and mark the insulation material with a pen or pencil, then use a sharp knife or scissors to cut it to size.
• Slide the insulation onto the PEX lines. Make sure the insulation fits tight around the PEX and covers it completely.
• Secure the insulation in place. Use electrical tape, clamping straps, or other appropriate fasteners to hold the insulation in place.

Install a Tiny House Water Heater

Installing a water heater in a tiny house is more challenging than installing one in a traditional home due to the limited space. Here are some steps to help you install a water heater in your tiny house:

Determine The Size and Type of Water Heater You Need

The size of the water heater will depend on the hot water you will be using and the size of your tiny house.

Choose a Location For The Water Heater

Install the water heater in an area with an easy access for maintenance and repair. It should also be close to the hot water outlets.

Install The Water Heater

Follow the manufacturer’s instructions for installing the water heater. It often involves attaching the water heater to the wall and connecting the water and gas lines.

Test The Water Heater

Once you install the water heater, to ensure it works it as follows:

• Turn on to the water heater gas line and set the temperature to the desired level
• Warm up the water heater for at least 30 minutes
• Turn on the hot water faucet in the shower. Run the water for some minutes
• Ensure the water is hot to your desired temperature using a thermometer. The temperature range should be within a few degrees of your desired temperature.
• If the water temperature is not within range, adjust the water heater thermostat until it reaches the temperature you want.
• Ensure there are no leaks around the water heater and plumbing connections
• Once you confirm everything is functioning well, turn off the hot water faucet

Follow All Local Building Codes and Regulations

Check with your local building department to ensure your water heater installation meets all necessary codes and regulations.

Tiny House drain plumbing

Drain plumbing for your tiny home before or after moving it to its final location. You must drain your tiny house plumbing after you complete the rough-in plumbing. It doesn’t matter where you position the house. You have to ensure the sidings and cabinets installation before you go on to drain plumbing.

Install Plastic Drain to Kitchen and Bathroom Sinks

Install the plastic drain pipes for kitchen, and bathroom sinks to prevent the grey water smell from reaching inside your tiny home. Use the S and P traps for the bathroom and drain lines. Manufactureres make these traps of plastic pipes connected to the kitchen and bathroom sinks.

Install the Bathroom Shower

You must install the shower drain following the manufacturer’s instructions. Install the bathroom shower as a complete unit. You must install the bathroom shower before you set the shower drain. This is because you must attach the shower drain to the shower drain point.

Install the Shower Drain

Installing the shower drain in your tiny house is compulsory to avoid the water logging of the bathroom. You must buy a shower drain fitting to your tiny home’s prefabricated shower stall. The shower drain often has PVC components linked to the shower stall drain.

Install the Subfloor For The Shower Waste Line Installation

It is vital to ensure you level and secure the subfloor before proceeding with the rest of the installation. When you don’t ensure to level the subfloor, it could lead to problems with the shower drain and waste line. If you need clarification on any installation process, it is always a good idea to consult a professional plumber or a building expert.

Combine All Drains Together

Combine all drain pipes and components into a single PVC line after the installation of all pipelines. Combining all pipes into a single PVC drain line removes dirt from your tiny house. To move away dirty water away from bathroom and kitchen sinks, use the 1-1/2″ plastic drain to 1-1/2″ PVC drain pipe.

Finishing Touches

The finishing touches need the lines connection and sections to a single drain pipe. Complete the connection of all the lines to a single drain pipe after you make all line connections. Attach two extra 10′ 2″ PVC pipes to extend the lines to the drain pipes. Move out and dispose of grey water as far away from the tiny home as possible.