I think the hissing is coming from the tank.
I know very little about plumbing so please explain as simply as you can.
Also, when I flush the toilet very little water comes down.
And do you know if this is urgent? How soon do I need to get it fixed?
The toilet just stopped hissing. It was probably hissing for 10 - 15 minutes.
Do I still need to get it repaired?
Not a fan
Favorite Answer
The water from the tank is slowly leaking into the bowl. The stopper valve that keeps the water from draining into the bowl and opens when you push the handle to allow the water into the bowl isn't sealing over the hole. You could just try jiggling the handle. The chain that connects the handle to the stopper might be too long and getting hung up on something not letting the stopper set down over the hole. The chain may be too short. It is not a big deal, There is nothing really wrong with it, and it will not do any damage. It is just annoying and wastes water. It can usually be fixed with a minor tweak. Brand new toilets can do this. Reach behind the toilet and turn the water off then flush the toilet to empty the tank of water so you can mess around inside the tank. If it is old you may just need to replace that hardware inside the tank.
glsorsdahl
chain on flapper needs adjusting and possibly fill valve has calcium build causing fill valve to slowly fill tank, replace fill valve