Tiny House

Small House Plumbing Diagram: All You Need To Know

By taufiqhaque

Plumbing is the process of building up a series of pipes and required appliances with it. It’s set up to ensure that water flow along the lines is adequately allotted around your home. Proper plumbing planning in your small house also reflects discarding water-borne diseases.  Read our article to know more on the small house plumbing diagram.

Plumbing was always an issue in any of the civilizations, whether it’s in the 50s or in today’s time. This is no secret that people were always looking for a functional water supply. It’s to easily get drinking water and to also manage water supply. 

Now, your question is how you will design an appropriate plumbing system for your tiny yet comfortable accommodation. After all, you need a water supply like any other homeowners for drinking purposes cooking. It’s also required for the reasons regarding sanitation.

How Easy Plumbing is for a Small House

Small House Plumbing Diagram

You might be an owner or living in a house that measures around 100 to 400 square feet. In other words, your house is the same size as an area where you can fit two average-sized cars.

Small house plumbing mechanism might sound relatively easy because your house is really small. On the other hand, it might seem too overwhelming for higher accuracy, and you need to pay more attention to detail. 

Fear not. From my experience, I found the construction of minor house plumbing is relatively easy. After knowing them, it actually doesn’t seem hard at all. The primary condition of being an expert in plumbing in a small house is a few simple pointers. 

Here, I will provide you with a handy guide about knowing all the mandatory tricks and the basics to understand how you can do plumbing for a small house. I will also cover the topic of how you can connect both washroom and bathroom appliances. We will also get an idea regarding the cost you will acquire when doing the plumbing yourself. 

Difference Between Plumbing in Small House and Big House

Generally, there are three main functions of plumbing that differ when it comes to doing at a small house or a big house. 


  • Installation of water tank 
  • Trailer management 
  • Determining how the water flow will come into your house

To understand from basics, it’s critical that you know the general foundation of the placements of the pipelines. 

The basic foundation of small house plumbing is as follows:

  • The first flow of water is to the cold-water inlet
  • The flow of water from coldwater inlet to a hot water heater and kitchen sink
  • Water from a hot water heater to kitchen sink and showers in bathroom 
  • Coldwater from the kitchen sink to showers in the bathroom too

Pipelines For Water Flow

Small House Plumbing Diagram

The complete list of commonly used water pipelines is:

  • Copper
  • Polyvinyl chloride (PVC)
  • Acrylonitrile butadiene styrene (ABS)
  • Galvanized steel
  • Chlorinated polyvinyl chloride (CPVC)
  • Cross-linked polyethene (PEX)

Various kinds of water pipelines are available in the market. I can suggest you use the most suitable one for the weather condition in your area. However, there is a general rule of thumb in the United States. It is that to use water pipelines made out of copper when you aren’t sure which type to use. 

However, copper lines might not be ideal for a small house. The reason can be that copper water lines are not highly bendable and possess a hassle when any breakage of pipes occurs. 

Specifically for a small house plumbing system, PEX might actually be most preferred. You can just cut the lines, clean, and then just connect in the fittings. The connections are also watertight. 

When purchasing the fittings, whether online or from a physical store, always mention them as ‘push fittings’ or ‘quick connectors. 

The fun part here is that you can never fit the lines to the connectors. Most brands of PEX allow. You to link them with water pipelines that are made of materials. It can be PVC, copper, or even CPVC. 

Now think of a scenario. Suppose you linked your water lines to the quick connectors not correctly. You can then easily separate them with a magnet. Then you will be able to connect them again. The crisis will eventually be solved! 

I can suggest browsing the plumbing equipment of SharkBites. SharkBites actually became a staple for PEX and pushed fittings. They are also one of Amazon’s Choice products. 

Their products are well known as they abide by the rules of both the residential and commercial standards of plumbing appliances in the United States. The price is reasonable and can be easily ordered on Amazon. 

Click here to check out one of the many Sharbite options for your small house plumbing. The product linked is a 100-foot coil along with push-to-connect fittings. It’s enough for your small house. The price range is in $$. Usually, the price is around 30-50 dollars.

I can also recommend using colour-coded pipelines to keep track of hot and cold-water lines. It’s common to use blue for cold and red for hot water. If the channels aren’t colour-coded, you can use some paint to draw just a strip of colour on the pipelines.

Lastly, one of the unique parts of PEX might be its bending capabilities. They can be bent around corners up to a certain point. There are instances you might kink the pipelines as the line’s surface becomes a bit ‘wrinkled’. If that happens in this case, then it is advised to change the water lines.

Size of Tube (in inches)The lowest radius of Bending (in inches)Lowest diameter of Bending for 90 degrees and 180 degrees U-shaped bends(in inches)

Pros: No need to use glue when connecting

  • It can be bent around corners 
  • Linked easily with quick connect fittings. 
  • It can be quickly connected without the extra hassle of completely changing the whole waterline system.
  • Reasonably priced
  • An excellent option for Do-It-Yourself (DIY) purposes
  • Resist temperature below freezing point


  • Highly sensitive to UV light
  • Liquid might enter older pipelines as they are semi-permeable 
  • Leach contaminants and other toxic chemicals 
  • It can easily be chewed by rats and other rodents 

Maintenance and keeping your house free of rodents is the ultimate key to not facing such issues above.

Small House Plumbing Blueprint 

I’ll consider that your home has one bathroom, a washroom, and a kitchen. Maybe you might have a washing machine too. Keeping that in mind, you can install a PVC pipe that is 2 inches for your drain lines. 

As water enters your house through a trailer, you’ll see the lines get divided. The first one is for the cold line, which will flow directly to your home. The second line goes to a water heater. Water gets heated depending on the type of heater you installed. I prefer a heater that can be switched on when required. This helps me to save electricity bills. 

The pipeline for cold water usually will enter your home at the back of the kitchen sink or cupboard. The line for hard water is split into different areas accordingly. Imagine being the branches of a tree. 

So the cold water lines get divided to be linked to washroom appliances such as the shower and sinks. Other lines are linked to the kitchen sink. The lines for hot water also follow a similar pattern as the cold water. This ensures you get both the hot and cold water in every appliance when needed according to your needs.

The direction of the line linkage also depends on where your shower and sinks are located. So, install the waterlines accordingly. 

Next, don’t forget about the drain lines! It’s fundamental to keep two drain lines. The 1st one is usually for the kitchen sink. The 2nd one is for your shower. They are always designed beneath them, and the drain is fixed on the floor to collect the incoming water. 

The drain lines are not separated. The incoming water from both locations might be collected in one RV sewer line or septic system.

Important Considerations of Plumbing Appliances

You need to understand that appliances for plumbing small houses are different from designing them for a big house. 

Water Tanks

Water Tanks are crucial for any house, whether big or small. On average, one household uses around 135 gallons per day. This includes everything from showering, washing hands, washing dishes in the kitchen sink, and whatnot. Surprising right? 

Now for a small house and 1-2 people, you have to minimize the water usage to a lower level. By this, it means to use 10-13 gallons per day. 

If you’re planning to place the tank on your trailer, be careful to distribute the weight of your water tank evenly over your trailer. Or else, you might face some serious consequences later. 

Pumping water from your storage tank to your sink comes with two options:

  • Foot pump sink from the water tank

The sink looks like the conventional one you see. The only difference is the paddle-like pumper attached to the sink below. You need to pump with your foot to get access to water flowing out of the pipe. This is an excellent option for trailers.

  • Volt pump sink from the water tank

It’s usually a 12-volt pump. You can go for this option if you plan to pump out a large amount of water at one go. The downside is that you will not get hot water when needed as soon as possible.

Water Hook-Ups

This can be done either for long-term or short-term purposes. Usually, if your small house is mobile, you can install hook-ups for a few years or even months.

Shorter Term Water Lines

RV water inlet is desirable for small mobile houses. Spigot is usually used as a water source here in such situations. Spigot is the part that helps to connect two separate pipelines or fittings. 

An ordinary hose can leach out hazardous components to any drinking water. So, don’t forget to use a safe drinking hose.RV water inlet is connected to the hose to create a drinking water channel in your small mobile house.

Longer-Term Water Lines

Direct connection is preferred for long-term plumbing usage. The PEX lines are usually buried below the hitch. To protect the PEX lines, you might need to consider insulating them properly. This will keep PEX lines away from experiencing harsh temperatures and avoidance from foreign chemicals.

Important Points

Now, you’re almost there to get a brief idea directing to the minor house plumbing. Before I mention the pointers, always remember to treat this article as a guidebook to get to know the most crucial points. 

If this is your first time, I highly recommend contacting an expert plumber or professionals who handle the plumbing system. But always get back to this article for a quick revision. 

The tips are:

  • Always remember the basics of plumbing: vents, pipelines, and traps.
  • 1/4-inch vertical drop per foot of pipe is the correct slope of plumbing 
  • A shower and a toilet can share a vent
  • Have an idea beforehand about repairing costs, especially pipelines
  • Tankless hot water heaters might be a great option for a small house
  • Discard old pipelines or fittings when they are disassembled 
  • Keep some access to your water lines 
  • Keep your house shut off in case of any leaks 
  • Handle and cut PEX with extra precautions 
  • Level your house properly 
  • Keep track of the temperature of both your house and the weather you’re residing at that time 

Final Statement 

Small house plumbing sure requires a lot of care and is not to be ignored just because it’s for a tiny house.

PEX lines might be your best friend during the whole plumbing process. It might become your foe if you don’t handle it with care and bend them more than what is stated. Also, ensure that all other appliances are fitted and constructed accordingly. 

Nevertheless, always be careful about any potential leaks or breakage of fittings and pipelines. You can keep some gaps or space to access the lines to keep maintenance every once or two months.

We tried our best to formulate a simple follow-through guide to know the basics of plumbing a small house. 

If you can follow through and get some help and advice from the expert, you might as well become a pro at plumbing one day. 

Happy Plumbing! 

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