I am in desperate need of help. My cat won't stop peeing outside the box.

We have 3 cats. Two are 15, one is 12. They've all been together for 10yrs.

My 15yr old calico will not stop peeing on everything. We had to replace the carpet (with pergo) bc of her. (Though we were going to anyhow.). Now she pees on the rug at the bottom of the stairs, or upstairs on the carpet about 3 feet from her box.

We have 4 boxes and we scoop them nightly.

I have tried putting a plastic drop cloth down over the entire area she likes to go in, and she will just pee next to it.

She's been to the vet. She had a bladder infection, and they have her antibiotics. It cleared up fine but the peeing (on the carpets) is still non-stop.

The vet wants to run all these expensive tests before trying anything behavioral. (And I'm fairly sure this is behavioral.)

I'm so irritated. I've read they need outside time, so we thought about an outdoor enclosure - the vet said it wouldn't help, and we'd have to get all 3 of our cats fully "outdoor cat" vaccinated.

The vet said to NOT change the litter - we had thought about that Cat Attract litter, bc a friend recommended it and I'd read a lot about it. She said that would be a huge mistake.

So I'm at a loss. I love my cats, and I don't really believe in getting rid of a pet. But I have two young kids at home, and I don't want them covered in cat pee, I don't have time to constantly be cleaning up after this cat, and I don't want all our stuff ruined. Plus come July it's our busy season and we won't be home as much to find the problem in time to clean it up.

2c/3a/3b, Fine/med, Dense, high porous, & normal elas.

Lo-poo - Renpure Keratin, SMR, Giovanni SaS
clarifying - mix Johnson's H2T with low poo
Co-wash - Suave Nats. clar. or coco.
RO - GVPCB, Ion Eff. Care, TN.
LI - SMR, Cure Care, or RO
Seal - MO or Jojoba
DT - + honey, ACV, & EVOO to SM masque & GVPCB
PT - Gelatin!, CNPF
Styling - FSG, AIF, BRHG, LALS/PS, GF curl spray gel, SM Souffle/Smoothie, LOOB
Oils - MO!, EVOO, jojoba, GSO, SM Elixer, EVCO, VO5 Hairdressing