What to Do to Toilets Before Vacation?

Drain the tank and add marine antifreeze to the bowl water, provided you do not have any animals that will be staying home that might drink out of the bowl.

Turn off the Water, Empty the Tank

Before you leave your house for a extended period -- no matter what season it is -- turn off the main water supply. After you do that, turn off the water to the toilet as added insurance and flush it. The tank won't empty completely, so sponge out what's left in the bottom and transfer it to the bowl. Note: Follow proper procedures to prepare all other fixtures and appliances connected to the house water supply.

Put Antifreeze in the Bowl

You can't completely empty the bowl because the water forms a seal that keeps sewer gases in the pipes and out of the house. Antifreeze prevents it from freezing. Do not use the type you put in your car; it will contaminate the waste system. Instead, use marine antifreeze, which also is suitable for recreational vehicles. You can find it at hardware and auto parts stores. Follow the instructions on the container to ensure you pour the proper amount into your toilet.