A toilet that keeps running after you flush it is really annoying. Mine has done it for a while and it usually stops if I tap the toilet a bit but that’s not really a fix it’s just a temporary solution.
There are two main reasons the toilet can keep running. One is a worn out flapper and the other one is the fill valve which might not be stopping to fill.
Diagnosing the problem
It’s quite easy to figure out is the problem with the flapper or the fill valve. If you close the water intake and the toilet still keeps running then you know it’s the flapper leaking and not the fill valve overfilling it.
This video should help you diagnose the problem and fix it.
Fixing the problem
In my case I had a the fill valve not stopping to fill the toilet. Fixing it might be as easy as cleaning the fill valve seal as shown in the below video. In my case this solved the issue of the toilet leaking which was great.
Saving some money
I have had another problem for a while as well: the fill valve makes an annoying loud whistling noise when filling up. According to the below video the best way to solve this is to replace the fill valve.
By doing the repair yourself you will likely save around a 100USD but you can save on parts as well.
My toilet has the Fluidmaster 400 fill valve. I live in Finland and the pirce for one of those is 69,90eur in a local Bauhas store. I think that’s crazy expensive. Luckily Amazon.de ships to Finland and the price is less than a third. Amazon.de even has free shipping to Finland if you order over a certain limit. If you are in the US the price is much lower. For current pricing check the links below.