Today I cleaned the bathroom

[Bunty55]

and put a new bathmat down in front of the shower.
I have three aging cats all over 16. two girls and a boy

Boycat likes to go in there and drink from the tap in the bath. I get this.. he likes fresh water. I bought a cat drinking fountain which is downstairs in the kitchen where they eat ( I have three cats) and they all drink from it but he still likes to use the bathroom.

They also like to pee in the shower. No problem. It washes away.

There is a cat flap in the hall so they can all come and go as they please but for some reason they like to go inside as well so I provide litter trays for all.

Today after I had cleaned the bathroom I walked in to see boycat on the bathmat scratching it up and I scooted him out.
He ran down the stairs and I saw him at the cat flap.

Next time I went back upstairs he had used the bathmat for a poo. Oh yes, he's done it before, but why wait until it is all clean and nice ?

He is an arsehole of some magnitude. He knows he should not do it but at this stage of their lives I suspect there is a little dementia kicking in.

I love them all dearly but when the inevitable happens I will not get another cat.

I will not. I won't. No. Not on your nelly.

Cats need a consistent scent profile in their homes so he was just trying to maintain it.

Ours would wee through the bannister all over the stairs. We had to remove the carpet after the second time. We have laminate on the stairs now.

Despite this we’d have him back in a heartbeat.

If he is old, he might be losing his sense fo smell. Shit smells stronger than pee. The reason he did it straight after you cleaned is because you cleaned his scent away. Annoying, but oldies are oldies.

Cats often scent mark new things - either by scratching at them, rubbing all over them or doing their business on them

You'll need to make sure you clean properly or he'll just keep going back to the same spot.