Can I get a discount on water charges?

Below is a note of how Scottish Water view customers usage of water that doesn't end up down the drain.
You might find it hard to demonstrate that less than 95% goes down the drain unless you are making ice or lemonade.

Volumetric charges for water and waste water
We charge you for the water you use and for treating the waste water you dispose of into the public sewerage system. Metered charges are applied to every property that
receives a metered water supply where the installation, type and size of meter have been approved by Scottish Water. If Scottish Water has not approved the installation, type and size of your meter, then you will continue to be charged on an un-metered basis, ie based on your property's RV.

If your property has a water meter, we base the water and waste water charges on each cubic metre (m3, equal to 1,000 litres) of water recorded by your meter. Since
not all the water you use will come back to the public sewerage system, your waste water volume is assumed to be only 95% of your water volume, unless you are a trade effluent customer. If you think that significantly less than 95% of the water you use ends up in the public sewerage system, please contact our customer response centre on 0845 602 8855 to discuss the situation further.