I would love a clean smelling house

[Isthereanicknamenotused]

I know there’s no real answer at the moment but my house stinks of cat pee. I have a cat who refuses to use a litter tray and prefers the floor in various places. I realise people will say “re home the cat” but she belongs to my disabled daughter and is frankly her life,
The cat has been checked several times by the vet and does not have any physical ailments to cause this.
She is an indoor cat, again, not ideal but this helps my daughter’s mental health.
Urine cleaning products don’t seem to work and I know there is no miracle cure but just wanted to get it off my chest. Thank you for reading.

Does the vet know why she refuses to use the litter tray? I think bicarbonate of soda is a very good neutraliser. With hot water it really does clean a lot of things. You could spray lemon juice as a deodoriser afterwards.

What have you tried to get the cat to use a tray? The main ones are:

move the tray- something may have spooked the cat where it currently is and shes too scared to use it.

take the roof off the tray if it’s covered or put it in a cardboard box / put it’s roof on it if it’s not.

buy feliway plug ins to calm the atmosphere.

remove other pets or people that upset the cat.

change the type of litter you use.

I have 2 cats. The boy cat gets annoyed and wees at the edge of a room (likes deep pile carpet).

Girl cat goes 'oh, is this where we're weeing now' and joins in.

They have multiple litter trays (which they happily and frequently use too, and I only buy boy-cat's preferred cat litter), and free access to the countryside around us, but they still do it.

Bicarb doesn't work.

Citric acid works a bit.

I got a big container of some german stuff from Amazon that you dilute 10:1 which works to a certain extent, but I've not managed to get rid of the scent in one spot still - to the extent that I think I'll just take up the carpet there and put lino down.

https://www.amazon.co.uk/dp/B09M49HNKS?ref=ppxyo2ovdtbfedasintitle&th=1

That's the one, there's also this one

https://www.amazon.co.uk/dp/B07PB1J339?ref=nbsbsswas-reorderk0110&amp=&crid=2NHNJYYZVIET3&amp=&sprefix=cat+urine+

But I need a lot more than a little spray bottle.

A UV torch can help you find the spots, but, it's not foolproof unfortunately - since other things fluoresce too, and if the carpet has those fibres it's hard to see .

Human urine cleaners do nothing.

I scrub the area at least once, often more, and keep them out of that area for a while. Sometimes they don't go back to it, sometimes they do, and I don't know how to tell the difference. I also watch out for them starting to do it and yell, chuck my sock at them chase them away in the hopes of putting them off doing it again.

Willow has had several tests at the vets to try to establish the reason but nothing came to light.
Thank you everyone who has offered a suggestion. I will take them all on board.