Pro tip: I put a brick in my toilet tank in March, and my water bill dropped $19
My neighbor Carl down in Tucson mentioned he'd been doing this for years, so I dropped a brick wrapped in a ziplock bag into the tank of my upstairs toilet back in March. My goal was just to stop hearing the tank refill for so long after every flush. The first bill came in at $19 less than the month before. I figured it was a fluke from being gone a few weekends, but it held at $17 to $22 lower every single month since, and that is real money when you are on a fixed city water rate. The weird part is I checked and my house uses about 3,000 gallons less per month now, mostly from that one toilet. I pulled it out and weighed it, and the brick soaks up water over time so it actually shifts around in there, which made me nervous it would crack the flapper, so I swapped it for a sealed 1 liter bottle filled with sand. Same result, less paranoia. Has anybody else messed with their tank like this, or am I the only one counting pennies in the bathroom?
Water displacement in the tank also means less cold water sitting in the bowl between flushes, so the toilet sweats less in summer if yours ever drips condensation on the floor. Might save you a towel.