Water consumption meter, consumption for a two-family house

Hello,

we are 2 owners and have a main water meter from the waterworks, as well as a separate small meter in each residential unit that measures individual consumption.

In recent years, everything has worked out, for example the entire house used 200 m3 according to the large meter, the 2 small meters always counted less. The deviation was always within the tolerance range of 5-7 m3. We divided that accordingly. The plumber once explained that this is normal and the two meters will never count the exact amount.

This year we received ready-made lawn and in a very short time watered a lot so that the lawn would take root. That means a lot of water passed through in 2 weeks.

Now the large meter shows a total consumption of 310 m3, but our two small meters together show 385 m3. So this time, for the first time, a much higher consumption compared to the main meter.

Could the reason be that we had this unnatural consumption through the sprinkler system and the meter is not keeping up (?)

Meters are designed for a specific withdrawal volume and withdrawal rate. A relatively large meter, for example, does not register a dripping faucet, whereas a small meter definitely "picks that up" (as I recall, a plumber once explained this to me in essence). I can also imagine the opposite effects. If your plumber has something to say, they should consequently install better or more appropriate meters. The deviation is already drastic and actually intolerable.