Claim additional operational costs. Until when is it possible?

In our new house build, the flat roof was installed so that the slope, contrary to the building description, faces the street side.

As a result, it is not possible for us to collect rainwater. This means that we have to use tap water for watering the outdoor area, and we also have to pay a fee to the city for the discharge of rainwater into the sewer system. We will incur additional costs of approximately 120 EUR annually. We want to claim these additional costs from our property developer.

we have not received a drainage plan. Since the front side borders directly on the street (sidewalk) and in our case it is a terraced middle house, we cannot set up a rain barrel here and must connect to the public sewer.

Hello again,

The drainage application is usually prepared in parallel with the building application documents, and the builder receives one copy each for their records, unless otherwise agreed; it is generally submitted to the responsible municipal utilities/drainage companies.

It is therefore important to clarify where and especially due to whose oversight the flat roof is inclined towards the street contrary to the agreement. I hardly believe that you will have a lasting claim for damages; perhaps an agreement in the form of an additional "bonus" or a credit is possible. But check carefully before whether you may not have actually signed approval for the orientation in the building application and, accordingly, agreed to the alignment.

Best regards