Low water pressure from the shower and washing faucets

Hello everyone,

a few details about the house:
Newly built in 2016, moved in September. Municipal water pressure according to the pressure reducer is 3.5 bar. Water softening system with 3/4" connection, Grohe Euphoria shower fittings.

My problem is that I have relatively low pressure in the showers and otherwise the flow rate is rather poor. The washing machine does not report any issues and I measured and got about 8 l/min in the showers and at the other fittings.
In the bathtub, however, it is already about 11 l/min.

In terms of the environment, it is of course great that less water flows automatically in my house, but it is not nice when instead of a powerful jet only a quiet dribbling comes out of the shower head. Unfortunately, there is no proper flow.

Now unfortunately I do not know what could be the cause. Could the flexible hoses at the water softening system play a role? As a test, I bypassed the system at the mixing valve but could not detect any difference.

Somewhere there is a problem, right, or are the 3.5 bar from the utility company simply not sufficient? Maybe the wrong hose sizes were used in general? Unfortunately, I do not know what has been installed, but normally the fittings have 3/8" connections and that is already small; I assume that everything before that is larger, right? Shouldn’t the flow speed automatically increase as the pipe gets narrower?

For your information, I have the same flow rate in the showers in the basement and upper floor. These are installed close to the municipal line (therefore only in one direction without circulation). I estimate the maximum length to be about 10 m.
The kitchen water is much further away (I think about 20 m), but the same rate of water comes out there as well.

I hope you can shed some light on this and provide me with a solution to increase the pressure on the shower.

Best regards

Modern fittings, at least shower thermostats, have a lock to help you save water. It can be overridden with the press of a button. Could that be the reason?
Best regards

Hello,

Water softening systems can have a negative impact on the pressure.
What does the pressure reducer show when a tap is in operation (this is usually less than the available pressure with closed taps)?
Is the pressure reducer fully open?
Otherwise, the fittings also have an influence, as written by ypg (in our case, they were already set to full flow at the factory).

Regards

Is there an outdoor water tap without gimmicks and without detours via any systems? How does it work there? Just for clarification. If it comes out full there, the water utility is innocent.

Hello,

Thank you for your quick response.
There is no save button on the fitting; I can only switch between the hand shower and the overhead shower. However, it is quite possible that there is still an adjustable valve inside the thermostat itself. I unscrewed it once, but with my layman’s eye, I couldn’t really discover anything, and unfortunately, I couldn’t find anything online either.
However, I don’t have a thermostat in front of every valve, and even the fittings that go directly to 3/8”, like in the kitchen, have a low flow rate.
As soon as I open the water line somewhere, the pressure drops at the pressure reducer, which is fully open. I have no idea to what value; I will observe this tonight.
Is there a value I should expect there?
We otherwise have about 16°dH, and I definitely wanted to install a water softener in between, but even if I bypass it, the flow rate does not change. However, to operate it properly, a loop was additionally laid upward, where I then inserted a mounting block with a mixing valve, and then it continues to the heating system.

Edit due to Nordlys’s post.
Unfortunately, I don’t have an outdoor faucet, but I imagine that the pressure in the line for the washing machine was higher when I tapped water there for the construction. Otherwise, I will also try to measure directly at the mounting block before the connection to the water softener as a test.

Is the pressure in the shower regulated only via the flow rate, or can the flow speed be subsequently increased by introducing some kind of narrowing?

Best regards

I have already had handheld showers whose nozzle settings were simply stupid. There are dozens of spray types to choose from, and with some showers, everything is just soft. Rainshower showers are supposed to pearl finer (is that how you say it?!), so as not to produce a hard jet. With an acquaintance, they forgot that with such a large showerhead a bit more water also flows through - the pipe diameter should probably have been bigger. How soft is the water now? That also feels different when it has been significantly softened. 8l/min is the category of a good water-saving showerhead. For Rainshower, it really seems to be a bit too little.