The first application of water is the most important and uses the greatest quantity of water. A good soaking requires at least 1 inch (25mm) of water to be applied as:

The above table indicates the amount of water needed for the initial soaking of the lawn and the approximate cost on a metered water supply.

To apply the recommended 25mm (1 inch) of water to a 100m2 newly laid lawn you need 2.5m3 of water – this will cost around £2.22 based on 1m3 costing 89p.

Daily top-up waterings will generally require lesser amounts to be applied but a great deal depends on levels of evaporation due to temperature and wind. If it rains during the establishment phase then some reduction in the water applied can be made, but only if the rainfall is lengthy and persistent. Short showers may seem sufficient, but a lot of this rainfall does not penetrate and just runs off the surface.

A simple test to see if plenty of water has been applied is to push a long screwdriver into the lawn. If it penetrates easily and deeply (9") then probably sufficient water has been applied.