There are many varying types of synthetic grass on the market. The Synthetic grass used for The Pet Loo Kitty Kat is of optimum quality to reduce your hassles. After lengthy testing, we have ensured that the perforations on the base mat guarantee maximum drainage. The grass only needs to be replaced if you feel it's necessary (click here if you would like to order more Pet Loo grass). For cleaning purposes pour warm water over the grass daily or alternatively lift it out and hose it down (in the shower if necessary) - remove the grass to allow it to dry. For times when The Pet Loo is not in use (eg: overnight) remove the grass from The Base to air it out.