Rolled turf or sow yourself??

Then you haven't searched properly ;) there are quite a few posts regarding this here in the forum alone. I'm currently on the go, so I can't write much. Where does the water come from (well, cistern, tap…)? Once you know how much pressure and flow rate you have, you can continue planning.

We are currently still planning our new building The house unfortunately is not yet built We are building with a developer We will not get a well or cistern We will only get a standard 3/4" KWA connection in the garden Unfortunately, we have to water with drinking water

First, think about what you really want.
lush, thick, green lawn without weeds (English lawn)
or lawn with weeds, sometimes brown

There are always restrictions on the withdrawal of drinking water. Short-term because the summer is extremely hot and dry or long-term like now in Brandenburg/Grünheide. Contemporary gardens should largely manage without additional water or with what the rain barrels provide. There are also large models in not only green.

We just want a standard green lawn

basically the sports and play lawn

In our region, there was only one watering restriction with drinking water and only for 2-3 weeks (but as the saying goes, no plaintiff means no judge :D)

So your garden is a 10 x 20 meter rectangle. That makes irrigation significantly easier. Rule No. 1 is that the sprinklers must overlap each other (head to head). So you place the first sprinkler in one corner. The next one at 10 meters, and so on. That way you can manage with 6 sprinklers. Use Hunter's pressure-regulated housings Pro-Spray PRS40. Irrigation head MP3500 (range approx. 10 meters). Your pressure and flow rate will not be sufficient to run them all at once. The MP3500 requires about 0.29 m3/h at 90°, about 0.65 m3/h at 180°. Therefore, I would group the 4 sprinklers in the corners together and the two on the long side. This way you would have two circuits with identical flow rates (1.3 m3 per hour should be feasible through your outdoor water tap). With two circuits, you can also implement a very simple solution. Gardena has irrigation controllers for two circuits. Simply connect it to the water tap and a connector from the sprinkler line to Gardena each. It has nothing to do with intelligent control but it is sufficient for comfortable irrigation. This way you save valve boxes and a proper irrigation controller.

There are many regions with short or longer extraction bans or maximum amounts. They are not without reason. The water suppliers find out promptly through the digital water meters. My uncle faces penalties. They are said to be quite substantial. installed a gigantic cistern and manages without drinking water. Take a look at his thread. Worth reading and watching.