Could under-stairs cupboards be converted into a small toilet and basin?

[RustyRobin]

We have a split level property so the upstairs is accessed via a 7 step stairway. Under the stairs is a small cupboard (full ceiling height) which is used for storing vacuum cleaner and hanging coats. Next to this cupboard is a cupboard actually under the stairs so the two could probably be combined. I want to know if it's possible to make a small toilet with a hand basin in the space.

It is. How easy and costly it will be will depend a lot of the plumbing. Is there a water supply and sewage outlet close by from what’s existing in the house?

My friend did this. It’s possible. Will require taking up the floor to get to the soil stack though x

Is there enough height ?

We have done this using a similar cupboard, it was a larder and under stairs cupboard. Fortunately we also had a window, but you will also need a fan for ventilation, required for Building Regulations. We had to insulate the walls as we couldn’t put heating in.
We had water from the kitchen (next room), we did have to move the electric meter to the outside which was costly. Our soil pipe was immediately outside as the bathroom was above, so that was an easy connection.
It is unwise to put in a downstairs WC without Building Regulation approval and signing off as it will cause trouble when you come to sell.

It depends on whether you can get the right slope to the soil stack. If you can't it will have to be a macerator, which is a pain.

Why though? A storage cupboard is far more useful than an additional toilet.

We have one. We have one of those toilets with a basin in the cistern which really helps if you're short of space.

Thanks

You just get indemnity insurance. It’s not a big deal

What’s that based on? You have no idea how many people live there or how much other storage they have. I’m sure the majority of people would prefer an extra loo if they only have one.