He's started cocking his leg in the bloody house!!!!!!

[ProcrastinatingPat]

I have an 8 month old Border Terrier. I love him completely. He is (or so I thought toilet trained. However I just noticed today he has started cocking his leg inside, despite having full access to the outdoors. He's done it on the door curtain on the way out and on a basket full of clean washing
What's that all about and how do I stop it? Please.

He's marking your house - is he neutered? That stopped it with our dog but if it goes on too long it becomes a habit which is quite hard to break

We cleaned really thoroughly with simple solution and watched him like a hawk around the 8 month period - he never did it in our house but did at friends' places and at pets at home (oh the shame)

Lol.. No he hasn't been neutered yet. But I'm gonna book it tomo. I don't like this.

Oohh borders are a stubborn sort lol. At eight months he's now the equivalent of a teenage boy, complete with paw stamping tantrums and a talent for seeing how far he can push you. Useless fact but this is the time many dogs are put into rescue because of this regression phase.

All you can do really is keep reinforcing the good and ignoring the bad. Treat him as a small pup again with frequent toilet trips. It does pass fairly quickly. I renamed my Scottie 'Kevin' through this stage

You need a blacklight/ultraviolet light to see where he's been - biological stains glow more. I got one for £5 in Maplin.
You then need biological washing liquid/powder mixed with water to clean it.
Normal cleaners contain ammonia which encourages them back. They'll keep going where they've been before otherwise

But on the plus side as you crawl around the house on your hands and knees witha UV light you will feel just like dexter at a crime scene

Apparently simple solutions doesn't contain ammonia. So I've been told. I've been using biological washing powder and it hasn't made a jot of difference, Monty still pees in the same place on the kitchen floor. Perhaps it depends on the type of powder?

Thank you all so much for your advice. I mentioned having him snipped last night and my hub and teenage son were horrified lol.

Neutering won't necessarily stop it, even dogs that are neutered young enough that they haven't started scent marking yet still do it.

As tabulahrasa says, neutering isn't guaranteed to stop marking in the house.

One of mine started doing it at around a year old, he was castrated and it had absolutely no effect whatsoever.

What did work was regular toilet trips outside, not letting him wander around the house on his own and cleaning up any spots he did manage to go in with Simple Solutions Urine Destroyer until he just grew out of it.

Personally I wait a bit longer til they are fully grown before neutering. Bostons are lovely dogs. Small fun full of energy.

Marco, op's dog is a border, not a Boston.