Toilet runs when sprinklers are on?

Question

I have a sprinkler system built-in to my house. I have a big yard so it is a heavy-duty system. I have it set to run every morning at 6:00 am. Every time it gets to the middle-right zone (about 45 minutes into the watering) my downstairs toilet runs. It doesn't flush just the tank makes a refilling noise. I am scared to use that toilet now because one time I was having a serious sit down and it started running and so did I. Yeah and then it started leaking water out of the tank mid-dump. I had to go upstairs to close- up shop. I started skipping that zone and doing by hand with a hose and nozzle.

Help!

Answer 1

your flapper is probably weak and has a slow seepage.  the ballcock is ready to add water and the drop in pressure just happens to trigger the toilet to start filling again.

replace the flapper and rebuild the ballcock for good measure.

Answer 2

I hae a similar problem at my house and it's caused by the changing pressure when the sprinklers come on and shut off.

I don't have a pressure regulator on my water main (apparently not required by code, because I had the house remodeled a couple years ago and it passed inspection). But, I noticed that the toilet runs every now and then whenever we turn on and then turn off the shower (it's a rain shower head that uses a lot of water). Apparently the changes in water pressure are enough to actuate the fill valves in the toilets for a few seconds (I have 3 toilets and sometimes they all 3 start running at the same time when this happens).

The only problem you have is maybe the toilet running when the sprinklers come on wakes you up at night. That is, there's no reason for you not to use that toilet when it starts running like that, just like you can't hurt yourself by flushing the toilet while sitting on it.

Answer 3

no, it's only coincidental. Once the toilet tank has filled, no outside factor can affect it...absolutely not!

It's in the toilet itself...probably the flapper, allowing wather to seep down the drain, therfore triggering the fill-valve to let water in..

Answer 4

You need to repair or replace the ballcock due to the pressure drop the seals are not holding in the ballcock they are old and worn. the ballcock should snap off instead of slowly shutting off!