Planning guest WC in new construction - How big should it be? (DIN?)

Hello house building forum,

we are currently planning a semi-detached house. The building window is very small and the floor area correspondingly low. In order to achieve a reasonably usable living area, we want to keep non-living rooms small and rather allocate the gained space to the living rooms.

On the ground floor, we are planning a guest toilet without a shower. In other words, only a toilet + washbasin. Recently, I have been carrying my laser measuring device with me to friends and have measured various guest toilets. Conclusion: 1 meter width and 2 meters length are more than enough. In our case, the door would be on the short wall, the toilet opposite the door, and the washbasin on the long wall.

We are currently looking for a builder and have roughly presented our plans. A potential builder wrote that according to [DIN] the guest toilet must be at least 1.24m wide.

My Google skills have not been sufficient so far to find the corresponding regulation or [DIN]. The [DIN 18022] for bathroom planning seems to have been eliminated without replacement.

Is anyone familiar with this regulation? Is it not allowed to plan a 1 meter wide guest toilet in new construction?

Hello, I don't know the DIN, but I quickly measured the WC of an apartment built in 2009: about 111cm wide. I think that's good, I wouldn't need it wider. Less might be a bit narrow, since the door opens inward.

My parents have in the guest bathroom 1.2x1.1. Sitting is fine, but standing up and with the door that opens inward it becomes uncomfortable.

For such a small toilet, the door should open outwards anyway, right? "If someone ever collapses in there" is something I've read quite often. Our toilet is 1.03 wide, door opens outwards.

I also think that a mini guest WC is perfectly sufficient. Especially when every centimeter counts in the house planning. The only question is whether one can freely decide on the room dimensions in the new building or has to comply with some DIN standard.

we are currently planning a semi-detached house. [...] We are currently looking for a developer and have roughly presented our plans.

If there are rough plans, then present them here as well. By the way, you are looking for a general contractor, a developer refers to a different type of builder (which would also be better for you, but you cannot use one on your own plot). By the way, one should never plan one half of a semi-detached house individually!