Stock tank cold plunge: tank, lid and ice
A stock tank cold plunge starts with a 100 gallon farm tank at about $150. Which tank to buy, how to insulate it, the cover to make and when to add a chiller.
For a stock tank
- Rubbermaid Commercial Products Brute Stock Tank, 100 gallonUnder $300See it on Amazon
- Suoimk Floating ice bath thermometer with timerUnder $300See it on Amazon
The short answer
About $150
That buys the tank for a stock tank cold plunge: a 100 gallon plastic farm trough you fill with a hose and cool with ice. It works as it comes in a cool climate. In heat it needs insulation and a lid, and those matter more than the tank.
For a stock tank
- Rubbermaid Commercial Products Brute Stock Tank, 100 gallonUnder $300See it on Amazon
- Suoimk Floating ice bath thermometer with timerUnder $300See it on Amazon
What a stock tank cold plunge is
A stock tank cold plunge is a livestock water trough used as a cold plunge tub. Farm supply stores sell them in plastic and in galvanised steel, from 50 to 300 gallons. The 100 gallon oval is the one most owners start with.
This page is about the tank, the insulation and the lid. The full build with a chiller, a pump and a filter is in the DIY cold plunge tub.
We have not built one. The tank’s size is as retailers list it, and the rest comes from owner threads on the r/coldplunge forum, read in October 2026.
- $120–$195 What owners paid for the tank
- 100 gal The usual size
- About 835 lb Of water when full
- 38–42°F One owner’s winter water, no chiller
Prices and the temperature are owner reports from r/coldplunge. The weight is our maths: 100 gallons × 8.34 lb.
Which stock tank to buy
Buy the plastic 100 gallon tank unless you are tall or want company.
| 100 gallon plastic | 150 gallon plastic | Galvanised steel | |
|---|---|---|---|
| Who uses it | Most owner builds | Owners who want more room | Owners who like the look |
| What owners paid | $120 to $150 | About $195 | Not reported |
| Size | 53 × 31 × 25 in | Not confirmed | Varies |
| Making a lid | Easy: the rim is plain | Harder: the rim is grooved | Depends on the tank |
| Watch for | The drain needs an adapter | More water to keep cold | Ozone can corrode it, by one commenter |
Retailers list the 100 gallon tank’s floor at about 41.5 × 16 in inside, so it narrows towards the bottom. You sit in it; you don’t lie flat. One owner has used a Rubbermaid 100 gallon tank for two years and another has plunged in the 150 gallon for decades and still recommends it.
For a steel tank that sits in the sun, one commenter suggests painting the outside white to keep it cooler. If you plan to add ozone later, buy plastic.
Parts list for a stock tank ice bath
- 1×
Rubbermaid Commercial Products Brute Stock Tank, 100 gallon
The tub. Owners paid $120 to $150 at farm supply stores, so compare before you buy
- 1×
Drain adapter: 1-1/4 in male to 3/4 in female, and a 3/4 in brass tap
Turns the tank's drain into a tap a garden hose fits. Use thread tape
$6 to $7Hardware store - 1×
Rigid foam board, 2 in
For the sides and the lid. Owners say the pink board copes better with getting wet
Hardware store - 1×
Plywood, a tarp and rubber edging
For the lid. See the cover section below
Hardware store - 1×
Pavers or gravel
A level base that will take the weight
Garden store - 1×
Suoimk Floating ice bath thermometer with timer
So you know when the water is in range
Total for the buildAbout $150 to $350The tank alone, up to the tank with about $200 of foam and framing, which is what one owner spent insulating a tank. We have not built this.
How to set it up
- Pick the spot. Shade, near a hose, with somewhere for the water to drain. A full 100 gallon tank weighs about 835 lb before you get in.
- Make a level base. Commenters suggest compacting the soil, then gravel, then pavers. The tank only needs the ground flat.
- Fit the drain adapter. Screw the adapter into the tank’s drain with thread tape, then the tap into the adapter.
- Insulate the sides, if your summers are warm. Foam board in a plywood box, or spray foam.
- Make the lid.
- Fill it, add ice and check the temperature. Aim for 50 to 59°F to start.
For 100 gallons of 60°F tap water, about 51 lb of ice gets you to 50°F by our maths. The table for other temperatures is in how much ice an ice bath needs, and the range to aim for is in our guide to cold plunge temperature.
Insulating a stock tank
A bare stock tank has no insulation at all, and this is where owners say the money should go.
| Setup | Where | What the owner reports |
|---|---|---|
| Bare tank, no chiller | Wisconsin, on a three-season porch | 38 to 42°F through the winter |
| Bare tank with a 1/4 HP chiller | Summers of 70 to 80°F | Could not get below 54°F |
| Lightly insulated tank with a 1/3 HP chiller | Florida | The chiller ran around the clock to hold 48°F |
| Insulated tank with a chiller | Phoenix | Held 38°F through a record summer |
| Tank with 2 in of spray foam | Not stated | “Keeps ice way longer than without” |
The owner who could not get below 54°F swapped the bare tank for an insulated barrel and kept the same small chiller. The water dropped four degrees in an hour and a half, a change the owner says would have taken four hours or more in the stock tank.
Owners insulate in two ways. The first is a plywood box around the tank with 2 in foam board or poured foam filling the gap. The second is spray foam, about 2 in all round and underneath, which one owner had done by a shop that sprays camper vans. A cedar surround alone adds a little, by the owner who built one in a hot, humid climate.
Stock tank cover: buy one or make one
A stock tank needs a cover for three reasons: to keep the cold in, to keep leaves and animals out, and to keep children out. Owners either make one or buy a fitted cover.
The lid owners make:
- A plywood top cut to the rim. Easy on the 100 gallon tank. One owner says the 150 gallon is “much harder to cut” because its rim has grooves.
- 2 in foam board glued underneath, so the lid is insulated and sits down inside the rim.
- A waterproof layer between the foam and the water. One owner used a tarp.
- Rubber edging round the outside and a coat of waterproof paint, so it lasts and gives no splinters.
- Two handles on top.
A bought cover is quicker. Owners use fitted covers sold for stock tanks, and one who plunges in a 150 gallon tank says a ready-made cover “will fit it easily”. If you want a stock tank with a lid from the same maker, check that the listing says a lid is included.
Keeping the water clean without a filter
A tank on ice has no pump, so nothing filters the water. The Wisconsin owner noticed fine fibres floating in the water after a couple of months without filtration. Owners running a tub on ice with no filter change the water every week or two.
One owner stretches that to three months with a small pump and filter and a little bleach: two ounces on filling and a capful after each plunge. We have not checked that dose against a water treatment source, so treat it as one owner’s practice.
When to add a chiller
Add one when you are tired of buying ice or your summers beat the insulation. The cheapest working example we read is a $120 plastic tank, a $270 1/3 HP chiller and $100 of lumber, about $500 in all, which its owner says has run for over a year. The owner insulated the tank and switches the chiller off in the warmest part of the day.
Insulate first. A chiller on a bare tank runs constantly and still falls short. The cooling side on its own is in the DIY cold plunge chiller, the whole build is in the DIY cold plunge tub, and our picks are in the best cold plunge chillers.
If you would pay more to skip the insulating, a cooler is a stock tank with the foam and the lid built in. See the Grizzly cold plunge.
Common questions
What size stock tank do I need for a cold plunge?
100 gallons suits most people. It is 53 in long and 25 in high as retailers list it. Go to 150 gallons if you are tall or want more room, and expect a harder lid to make.
Can I use a galvanised stock tank?
Yes, and owners do. One commenter warns that ozone can corrode metal tanks, so choose plastic if you plan to add it.
Will a stock tank freeze in winter?
It can. One owner of a Rubbermaid tank broke through the ice with a hammer on the coldest days and plunged in the water underneath.
How do I drain a stock tank?
Through its drain plug. With the adapter and tap fitted, you connect a garden hose and run the water to a drain or a garden bed.