Seepage system, even though a cistern is in the development plan?

Sure, I meant the 3rd line just for the bathroom and guest toilet, with only the kitchen branching off anyway. Well, I will calculate it and discuss with the developer whether it even makes sense. Can you estimate about one euro water cost per day for the toilet with 2 people?

Let's generously assume 8 uses per day at 9 liters each (although most toilets nowadays flush with 6 liters), that is 72 liters; with water costs of €2.50 / m³, that is €0.18 per day (or €0.12 at 6 liters...).

I calculated it extensively for myself and ultimately decided against using rainwater; luckily, a cistern is not mandatory for me, and for garden irrigation I had a separate meter installed (costs €30 every 60 years) and I do not pay any sewage charges here.

No.... well, I don't know what water costs for you, but for us, 1m³ costs 1.38 + sewage fee 1.26 €. That means 1000 liters of water cost me 2.64 €. With a water consumption of 3-8 liters per flush, it certainly won't cost you €1 per day. So, per flush about 3 cents... so it depends on how often you have to flush :)

OK, may have been a bit optimistic... I am calculating with max. costs of €100 per year for 2 people, possibly a 3rd person will join in 1-2 years :-)

Hello,
If the development plan requires the installation of a cistern, it is advisable to first inquire with the building authority whether an exemption from the development plan or a deviation is possible. If so, then apply for an exemption/deviation as part of the building permit application.

The question is how meaningful this is. Although a soakaway pit is cheaper than a cistern, for a garden of 400-500 sqm I would recommend installing a cistern, as drinking water is far too valuable to use for watering the garden. A 5cbm cistern seems sufficient to me.

For rainwater use, a connection to the cold water system of the house is necessary. A third pipe is not required for this. The rainwater can then be used for garden irrigation, washing machine, and toilet flushing.

I hope I could be of some help.
Best regards
Hans Ma Wurth