Introduction: Rubbermaid Propane Heated Soaking Hot Tub (Ofuro Tub)

FITS 1-2 people comfortably... could have up to 4 people if you leave enough seating (just rest your legs in the tub). This tub is ~25-in deep and allows you to easily submerge most of your body or kick you legs up.

Why spend $3000-$5000 to get a professional hot tub installed and spend way more maintaining it???

With these plans you can get this done in 1-2 full weekends. I spent some time planning this but built this in two weekends (did the tub pump work first with a test to make sure it worked) and then put in place and did all the woodwork the 2nd weekend.

We really wanted to build a traditional wooden Japanese Ofuro tub after having a couple trips with hot springs that fed into these style tubs. We decided building a rubbermaid tub would be much easier to build and maintain. The plan was to use this for relaxation and for muscle recovery (cold or hot baths are possible).

Our budget for this was less than $1000 and we certainly did that. I think the number was around $750.

I'm not going to include all the details in this instructable because I didn't plan on making this an instructable from the get-go. I will include all the references I used to put the details together. I found some pretty useful videos and guides.

Before we start:

SAFETY - consider the loading of the ground. This is a 150 gallon tub which at 8.6 lbs per gallon plus weight of people and wood is around 1500 lbs of weight. Make sure you build this on a ground that can handle the weight. We considered having a contractor build a deck for us, but we decided to just set out two pieces of treated plywood to disperse the weight over the flagstone (which is good for draining water already).

Also need to consider electrical safety. Make sure you have ground fault protection, manage the electrical safely and know that water + electricity is dangerous.

The propane heater is a great way to go. Less cost and energy waste than electrical and less pollution and more control than burning wood. The propane heater doesn't get TOO hot and this setup is relatively quiet. I was quite impressed. As you can see, I chose a position that allows clear air access for the heater so that it is not a risk of burning anyone or carbon monoxide build-up.

OVERALL best guide for the pump, water filter, water heater, filter, materials/parts can be found on this youtube page. Make sure to click the links for materials on amazon. I used the same 8L heater and same pump. My tub can go from 75 deg F to 105 deg F in a matter of 30-45 minutes. I ordered extra hose, extra hose clamps, and extra adapters because I wanted to T-in the shower head.

We aren't in a very cold climate, but if you were it might be worth putting in some insulation. On a colder day (for us) of about 50-degrees outside the tub kept its temperature at 105 deg F for at least an hour.

This video shows a good overview of how to make use of the existing drain plug on the tub:

some more tips/inspiration here:


rubbermaid tank - 150 gallons - buy at a hardware store or tractor supply company. Was easy to call ahead and it fit into my SUV. This fit into my SUV almost to the MAX.


water filter pump: (you could also upgrade the model as reference in the youtube video)... this is the small one... not very strong but quiet:

Jet assembly (for the water filter pump - I couldn't adapt over the one that came with the pump, but this worked great

water pump (to pump into the heater):

GFCI power supply:

electronic shut-off/turn-on (no timer on this one)

temperature ducky:

1-1/4 in PVC drain hose connection

PVC hose adaptor (QTY 2):

flexible coupling for PVC and jet assembly:

PVC adaptor (in place of the drain plug that comes pre-installed):


Dont forget to get some stock 1-1/4-in PVC, and the primer/cement and cutters - 8-ft should be good

1/2-in hose adaptors:

1/2-in hose - need 1-2 of these

1/2-in hose spigots (need 2):

clamps for the 1/2-in hose:

if you want to add some valves and T-in the shower head:


plywood base (treated) or some other base build

plywood (use the highest quality) for the top seating and cover

exterior wood frame (i used oak)

4x4 and 2x4 or 2x6 to build frame-work - use treated if coming in contact with ground

a nice thin plywood for covering the interior (cut into pieces and screw in)... or do it a nicer way if you are more skillful

OTHER tools will be necessary to get the job done. Some are referenced in the videos.


Step 1: Flowpaths

These photos show the flowpaths of the parts.

The T with valve on the PVC is the drain. I would make sure that is accessible so you can drain the tub from time to time. Also make sure it is pointed downwards. I ended up connecting a hose and running that out to the drive-way to make sure it didn't just flood the immediate area.

The hose clamps need to be VERY tight on the bibb adapters (1/2-in). Make sure you tighten them up and look for leaks. They work well once you get them tight.

Make sure you consider the height/position of the inputs/outputs. You want the outlets to be higher but not too high. You will probably keep water filled to the 2nd rung on the tub or slightly lower. Don't expect a lot of bubbles like a traditional hot tub.

I am planning to cover this all up with wood at somepoint.

Step 2: Frame Build/Wood-work

These photos are pretty self-explanatory. Build the support beams, make sure they are as level as possible. Connect them, build the exterior wall, cut the top with a jig-saw, use the center piece as a top/cover for the tub and add handles at some point. Get the coating done to protect from rain/water

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