Determine the elevation of the manhole cover in the street, Water Department

Hello everyone!

My husband and I are currently in the middle of planning our detached house.
We have commissioned a soil survey to clarify whether and how we can build a basement.
Now the company carrying out the survey needs the height measurement for the manhole cover that is in the street where our property is located, in order to measure everything correctly.

Does anyone know where I can find this out, or which office/authority is responsible for such things? Is it the district office (Water Department)?

Thanks in advance!

Lilli

With us, before the soil survey, the surveyor came.... he then took the measurements... But the waterworks should also have this data

Hi Lilli,

as far as I know, this is not included in the data from the land registry office.

In my opinion, there are now two possibilities:
1. the surveyor, whom you need anyway for the official site plan, will also measure the manhole covers including height and then note them in the site plan. But I assume you are not yet at the point of commissioning a surveyor.

2. in the pipeline information I received from Berliner Wasserbetriebe, the height of the cover edge and the channel bottom are each specified for sewage shafts. You can get such information from your local water supplier or for a few euros at "infrest" (just google it). But of course, I do not know whether the heights will also be included in your pipeline information.

And I wonder why the soil expert cannot obtain such information himself. Furthermore, the absolute height is not important. It only needs to be ensured that he relates the drilling to a prominent point, e.g. [Kanaldeckel]. From the [Kanaldeckel] he can then determine the position of the drilling in all three dimensions himself.

Regards
klblb

Manhole covers,.... That is a strange approach. The manhole covers are not calibrated. There are (at least in our construction area) surveyed reference points specified by the cadastral office. The surveyor used these points to check his height measurements. Whether a layperson can access the data, I do not know. A small tip on the side: Other builders in our construction area skipped the leveling and measured based on the supposedly correct manhole covers. However, the covers have settled by up to 10 cm, resulting in completely incorrect property heights. In other words: Only a surveyor can specify a reference point – and this one should ideally be FIXED.

Hello everyone!

The tip about the utility information was exactly right. After countless phone calls with the district office and the city, I finally ended up with the right lady in the civil engineering department who issues this information. It doesn’t even cost anything and it also includes the manhole cover heights. We need this information anyway to connect our house to all the lines.

Since this is not about the exact centimeter measurement of a building, but "only" about a soil survey, I think such a manhole cover is definitely a fixed point that such a company can use for assistance.
At the two front corners of our plot, boundary points have been set (the small round metal plates), it is a gap in the old town center, but the company wants to work with the manhole cover.

Many thanks!

Lilli

Hello Lilli,

the manhole covers are completely sufficient for the ground survey. For safety, one either measures two different covers or opens a manhole and checks the invert depth, which is indicated in the plan from the civil engineering office. Usually, two heights are given per manhole cover, manhole cover and invert. The invert will not change; from the measured difference between invert and cover, one can calculate/check whether the cover height has been changed at some point. This is not unusual when the street has been newly paved and is one of the most common sources of error.

Best regards
Dirk Grafe