What can I use in toilets & drains to rid hard water build up?

vinegar. its a mild acid and will dissolve the lime scale. try letting it set over night and use a brush on it the next morning.

CLR is a good product to try and do-it-yourself folks always recommend white vinegar. If your water is so hard that it actually causes issues with drains you should have the water tested to determine hardness level and consider installing a water softener.

I had 22 grains of hardness in my water and it was causing issues with a tankless water heater. It would scale up then the scale breaking loose clogged the aerators in my faucets. One of the better things I did was installing a water softener.

vinager. Let set overnight. Scrub next day.

Use a good amount of white vinegar and let it set all night. (2 cups or more). It is easy to scrub the toilet bowl after soaking all night with vinegar. Hope this helps

I use The Works on my toilet bowl. It is cheap and works fast! CLR is a must for everthing else. We soak silverware and dishes overnight as well. We get scale on everything. It is a miracle!!