Pumping system or natural drainage over a 40m channel

It also depends on what kind of property it is and what is already on the intended pipeline route...
And how much really goes over the neighboring property.
Also to check: over 40m with 2% is 80cm. + 80cm because of frost, that’s already 1.6m. Is the sewer connection then still deep enough (normally yes, but better to check).

To my knowledge, 1% is sufficient for 110mm pipes.

Also to check: over 40m with 2% is 80cm. + 80cm due to frost, that's already 1.6m. Is the sewer connection then still deep enough (normally yes, but better check).

Since the neighboring property probably also has a slope, that probably shouldn't be a problem

We have about 60-70m of wastewater pipe to the sewer with the pipes under the slab. A 100mm pipe with a 1% slope is sufficient. It is also preferable to any solution with a lifting system, which costs money and should be serviced annually (it cannot handle individual socks). The slope should be followed exactly, and the low flush button on the cistern is taboo. Once a year we empty our cistern to flush the pipe. There are 2 inspection openings in the pipeline, which are great for disposal for motorhomes.

If you decide to go across the neighbor’s meadow, under no circumstances without a pipeline right secured in the land register.

We also bought an old meadow through which two neighbors drained their houses, both without registration. One was allowed to stay (still without a registered pipeline right and without a real alternative), the other had to have a lifting station built for a total of €35k because the pipeline ran straight through our building area.