Dog's Water Bucket Heater





Introduction: Dog's Water Bucket Heater

About: Professional Engineer with The Vecino Group.

If you live in an area with cold winters and have a need for an outdoor water bucket for a dog, you know that keeping it free of ice in the winter is a problem. I'd seen simple little heaters like this used in chicken coops, and decided to see if it would work to keep our dog's water bucket thawed. It worked perfectly, and didn't take more than 15 minutes to make.

It's just an 8" metal cookie tin wired with a light bulb inside, which serves as a heated base for the water bucket. A 40 watt bulb generates enough heat that it has kept our dog's 5 gallon bucket completely free of ice on nights that went into single digits, yet the surface of the tin never gets more than warm to the touch. On mild days in the 50s, even with the heater still on, the water stays cool.

You can see from the picture that a tin smaller than 8" diameter may be too small to fit everything inside. You'll also need the wire, plug, threaded pipe, nuts, and bulb socket which hardware stores usually sell as kits. I had an empty tin from Christmas and all the wiring gear except the socket on hand, so the whole thing only cost me $4. For added safety, cut the female end off a short length of grounded outdoor extension cord and use that instead of the lamp kit cord, which is likely not meant to be outdoors.

Drill a hole through the middle of the side wall of the tin the size of the lamp kit's threaded pipe (probably 3/8") and assemble the socket and wire through the hole, connecting the ground wire to the socket or tin.

Keep water out in case of spills or splashes with a dab of silicone sealant or anything else that will seal the gaps where water might be able to get in around the socket. The lid fits down over the bottom snugly enough that water isn't going to get in that way unless it got submerged. Even with that though, I'd want to keep this where it was reasonably well protected from the weather. Mine is on a covered patio, where blowing rain is the most it should ever get. Put the lid on the tin and set the dog's bucket on top.

If you want automatic operation and don't mind spending a little more, you can find a device called Easyheat that will turn on/off the electricity as needed.

The first night I used this, the bucket was frozen solid, so I brought it inside to thaw. When I took it back out to fill it, I didn't notice the ice had created two small leaks in the bottom. So for the next couple of hours it slowly emptied all over the heater. When I discovered the empty bucket, I checked the tin and it was still completely dry inside and the GFCI had not tripped. That helped convince me that it was adequately safe.


  • Know what temperatures your dog can handle and bring them inside when it gets too cold. I'll assume you already have a doghouse for wind and rain shelter.
  • Make sure that this is plugged into an outlet that has GFCI protection. It's been common for building codes to require exterior outlets be protected for at least 20 years, but don't assume yours are if you don't know for sure. Check it and don't run the risk of electrocuting your dog or yourself.
  • If your dog chews, you'd want a chewproof cord or maybe protect it by running through a length of old hose.
  • The cord in your lamp kit is likely not meant for outside so if you opt to use it, keep an eye on it to make sure it doesn't develop any breaks in the insulation from exposure to sun and cold. For extended use, it would be good to find outdoor rated cord or sacrifice a short outdoor extension cord to use instead.



    • Backpack Challenge

      Backpack Challenge
    • Stick It! Contest

      Stick It! Contest
    • Creative Misuse Contest

      Creative Misuse Contest

    28 Discussions

    Per suggestions for better safety, I updated the cord on mine this evening to use a 3 wire outdoor cord and have the whole thing grounded.

    I didn't know that a light bulb could produce enough heat to warm up the water in the pail. Even if all you need is enough warmth to keep the water from freezing, that's quite a lot of power in one bulb. It's definitely an easy way to keep your dog's water from freezing over during the winter. Thanks for the advice!

    There are a number of ways to improve on this idea. First you need 3 wire for adequate ground protection. the wiring needs to be rated for outdoors, not just shoved in a garden hose. I would suggest UF direct burial cable or a rated SOOW cable. If damage protection is needed use electrical rated pvc conduit or sealtite.

    Honestly your best approach would be to use a UL listed product like an EASY HEAT - heat tape for this. This would allow you to heat the container without direct contact with water unlike an aquarium heater which would could be damaged from a rouge pup strike. Incandescent bulbs require air in order to maintain proper temperatures to avoid fire and premature failure, so avoid shoving then into a closed box. In addition using a designed heating product will use nearly all of the energy for heat instead of light.

    - licensed electrician

    Great idea, thanks for showing this to me as I'm trying to make a heated birdbath to put out this winter. I'll do something similar to this except I'll be insulating the water tank with pink house-insulating foam--less energy required to keep the water melted.

    And I like the idea of protecting the cord from the dog with a length of old hose, but if you do that, never run it in temperatures above 60 or in areas with flammable materials. It's unlikely that double-insulating the wire with the tire-rubber would cause a fire, but it could.

    Go to the fish store and get a aquarium heater, a bit more expensive but made for safe and continuous water heating, on amazon for $10

    I had made something similar at one point as well. if the sides and bottom are insulated, the losses would be minimized... fiberglass insulation would work

    @jmwells. ??

    Seems like some one doesn't like negative comments, or wut?

    Has this comment been removed, or am I blind as a bat?

    If something happens and water meets electricity, the GFCI will pop. It's the same thing that's in your bathroom or on the end of the hairdryer cord that keeps you safe it you drop it in the sink. The weak link of this project is the cord, as it's likely not meant to be used outside. I'll keep an eye on it and probably replace it with a length of outdoor extension cord before next season. In fact, I'm going to update that safety tip with that suggestion.

    The Danish SafetyTechnology Authority found that 9 % of GFCI do not work, even though the testbottom still worked on half of them. So dont be so sure that it will always work.

    You can improve the safety significantly by using a 3 wire cord in a grounded socket ( this is pants and suspenders ). The cord could be protected in a number of ways: segments of pcb pipe, inside an old hose.....

    Another approach ( in addition to the above ) would be to use an isolotation transformer, or a low voltage transformer with a low voltage bulb.

    5 replies

    Not true. The alternative bulb may be more efficient and transfer more the power into light energy than heat energy.

    I had a bit of a "derp" moment when russ_hensel pointed out that the heat output is the same for equal watts, but then I had the exact same thought you did. It took a little thinking about it to realize both things are true. A ray of light doesn't just continue bouncing around a room, or in this case the tin, forever. If it did, you could turn off the light and still be able to see it. The light energy strikes the walls of the tin and eventually all of it gets absorbed in the form of heat. So it doesn't matter what percentage of that input energy initially goes into heat vs light. It will all be heat eventually.

    As electican I will subscribe to the low voltage variant. Connecting earth wire is safe if a cable connects the tin to blow the fuse then instead setting the bowl under 220/110 volts. But it not prevents the dog from electric shock while chewing the wire!
    Fi switch will disconnect power in this case. But who wants his pet become a laboratory animal testing the proper function of the Fi switch?

    My opinion. Water+Power+DIY only with low voltage and transformer!

    A 21 W brake light bulb from car will do the job with a ascending transformer.

    I like it. Do you just leave it on all the time? Does the bulb blow often? If so, oven bulbs will probably withstand temperature changes a bit better.

    1 reply

    The weather has been such that I've left it on. Days maybe get into the 50s but we are still going below freezing each night. So far, no blown bulbs. I measured the temperature of the tin last night. It was 105. I'm curious if a 25W would be enough to do it.