How much pressure is on the cold water line?

Hello,

I wanted to ask you what the optimal pressure on the cold water pipe is?
We have a semi-detached house and bathrooms and water connections on a total of 3 floors.

The water connection is in the basement and we have a washbasin in the basement.
On the ground floor we have a guest toilet and on the upper floor we have a bathroom with a bathtub and shower.

Currently we have 3 bar but for example in the kitchen the water pressure is rather low (possibly also due to the faucet). The lawn sprinklers don't reach very far either.

What would be your recommendation for the water pressure?
What is the upper limit before it becomes harmful for the pipes and fittings?

Generally, 4 bar is assumed, although I would rather locate the problem in the kitchen at the faucet. Often there are some ridiculous water-saving inserts in there that negatively affect the whole thing.

I can't say anything about watering - the lawn has to fend for itself here.

I myself run the place at 3.5 bar - but that's more personal, I also tend to drive my vehicles at low revs...

I have also read that 4 bar is standard. But to be honest, I wouldn't even know how to check that myself. Open the valve into a 10l water bucket and time it? That strictly speaking is only the flow rate. For the pressure, something else must be involved, right?

Generally, 4 bar is set, although I would rather localize the problem in the kitchen to the faucet. Often there are some nonsensical water-saving inserts in there that negatively affect the whole thing.

Is 4 bar the standard that one sets, or should 4 bar be the upper limit and not go higher because, for example, starting from 4.5 or 5 bar it becomes critical or harmful for pipes and fittings? There are certain fluctuations in the line anyway.

We currently have 3 bar; I would increase that to 3.5 or 4 bar.

Honestly, I wouldn’t even know how to check that in my place.

We have a water filter in the basement where we can check and adjust the water pressure.

For me, the water runs directly from the supplier into the house without a pressure reducer - it is always between 4.5 and 5 bar.

is the 4 bar the standard that is set or should 4 bar be the upper limit and not go higher because, for example, from 4.5 or 5 bar it becomes critical or harmful for pipes and fittings?

It is not critical. Except if some rubbish was done that would then cause it to burst apart.

Inside the house, 3-4 bar is "usual," in multi-family houses less often reaches the upper floors. Suppliers usually run between 4 and 8 bar into the house.
Your house installation should be designed for 10 bar. So there is more than enough margin.

Strictly speaking, that is only the flow velocity.

No, that is the flow rate in l/min,
flow velocity in m/s is irrelevant in a single-family house.
Between 3-4 bar is set on the water filter pressure reducer

For example, the water pressure in the kitchen is more than weak.

Possibly unscrew the faucet outlet, put it in a cup of vinegar essence, rinse with water after a few hours, and reinstall.
With Berlin water, this is necessary annually.