Estimation of development costs

Hello everyone,
we are planning the construction of a single-family house over the next six months. At the moment, I am intensively dealing with the ancillary and development costs. The costs for supply and disposal up to the property boundary were easy to determine, but it is more difficult with the internal property development.
Planned is an "Erschließungsgraben" in which electricity, fresh water, wastewater, and rainwater drainage will be laid over a length of 35 meters.
Unfortunately, I was not able to reach one of the local civil engineers for a cost estimate during the holidays. Since we have an important appointment at the beginning of the year, where these costs will probably be relevant, I would be very pleased about an estimate from you.

What is the cost of excavating an appropriate trench, installing the aforementioned utilities, backfilling, and leading the lines into the basement approximately?

Thank you very much for your effort.

Best regards
space78

Hello space78,

are your utility providers informed that you have 35 m distance to the house? What do the guys from the water department say, is a transfer point planned? How deep is the sewer? At 35 m your wastewater on the street is already somewhat deep below street level, right?

Once you have clarified all this, one utility provider can take the lead and create an offer for you.

Hello,
the suppliers, meaning providers for water and electricity, know about the 35 meters. Water will be laid up to the property boundary and a meter inspection chamber will be installed there. I already have the price for this. Everything else on the property I have to lay myself or contract to a company (whereby I plan the latter). For the electricity connection, I also already have a final price up to the house (trenching done by myself).
The property has a constant, slight slope, therefore the house is significantly above street level.
I now need a cost estimate for a 35-meter-long trench in which the water supply (material costs for the pipe according to the supplier about 5 euros per meter), the electricity supply (cable already included in the connection price), as well as the sewage and rainwater pipes (material costs per meter are unknown to me) are contained. The whole thing must be excavated, equipped with the above-described media, and backfilled with sand or the excavated material. How wide and deep it must be excavated is beyond my knowledge. I have heard that when equipped with the media I planned, the trench should be 60cm wide and 140cm deep.
Regards
space78

From a depth of 1.2 meters, I think you need sheet piles. For backfilling, compacting, etc., I would cautiously estimate around 100 m3. So about 3k.

Thank you for the assessment. So about 3000 euros for the earthworks. What else do I need to calculate additionally for the wastewater pipes and the transfer shaft for sewage?

Regards
space78