Optimal pipe diameter irrigation system

Hello everyone,

we have the opportunity to have a separate water line installed on short notice directly from the main line through the basement wall into the garden. The goal is to enable an irrigation system later. However, there is no detailed planning for this yet, and the implementation is to take place only after moving in. The free garden area is >1000m². Initially, we would just have the line laid into the garden so that splash protection and pathway paving are not hindered later.

Now the company is asking us for the desired pipe diameter and suggests 3/4". Without really knowing much about it, that seems quite small to me. A thicker pipe practically doesn't cost any money, but what would be a reasonable diameter? 1"?

Regards

It would make sense to completely avoid using tap water for the garden area. Then the question does not arise. You can invest the money better. Otherwise, follow up to check if 1 inch provides enough pressure.

Pay attention to two things: definitely have a shut-off valve installed exactly at the branch in the basement! Then plan where the valves and the control should be located later. There needs to be electricity there accordingly.

We have 3 circuits, all in 3/4 inch. For you, I would rather tend towards 1 inch. For you, it will probably come down to around 5 circuits.

It would make sense to completely avoid using tap water for the garden area. Then the question doesn't arise.

and where should I get water then?

Then the question doesn't arise. You can invest the money better.

Currently, it is about an investment of maybe 200€ for a measure that I could no longer catch up on later. You probably mean a cistern; aside from the problematic deep excavation here, it would never be economical. We pay neither rainfall charges nor wastewater fees for the garden water.

Pay attention to two things: definitely have a shut-off valve installed right at the branch in the basement! Then plan where the valves and controls should be located later. Power needs to be supplied there accordingly.

Shut-off valve with drainage is clear; the garden meter will also be placed there. I have power: a UV in the garage with an outlet to the garden, so we stay flexible. It will be a few meters, but the electricity doesn't care. Detailed planning is difficult right now, also budget-wise. That's why the plan was to first bury the water pipe with a generous loop.

Thanks for the assessment; then we will go with 1". We cannot influence the pressure, but it's certainly better than the previously planned outdoor water tap.

and where do I get water from then?

For example well, cistern, etc.?

Currently it’s about an investment of maybe €200 for a measure that I could no longer make up for later.

They don’t care either. The countless cbm of water (therefore at least install the separate external water meter to save wastewater) will make you poor. Better to plan a few thousand € for a well (with a reasonable groundwater level maybe only €800 including pump). Tap water is only economical on such a property if absolutely nothing else is possible.

Example: a simple Gardena Polo garden sprinkler (approx. 200sqm lawn is watered) uses about 1.2 cbm of water per hour (at 4 bar pressure). You have more than 1,000sqm = at least 5 pieces = at least 6 cbm per hour. How much does water cost for you? €2.00/cbm (probably a bit less + meter rental)? Additionally beds, maybe a pool...
You can quickly estimate what the tap water costs with that.

There is no groundwater (Grundstück auf dem Berg) and rock is expected at 1.5-2.0m. Any deep excavation can become a harakiri. We were lucky with the basement because the ascending rock base starts there and our basement floor lies exactly on rock.