Competing groundwater use is a problem in the vicinity of the Mount Barker Golf Club grounds, which has been recognized by the parties involved and government since late 1985. A well monitoring network for both water level and salinity was set up and first read in April 1986. The network is monitored monthly. Between 5 July and 12 July 1989 two wells used for market gardening, which are located adjacent to the two Golf Club irrigation wells, were test pumped by SADME Groundwater Branch personnel, with the hydraulic recovery efficiency of the water table in each well then monitored for an extended period after pumping. Monitoring results indicate that all wells in the area are exploiting the same aquifer system; further, the wells are capable of appreciable yield interference; locally the standing water levels have been lowered by 10 metres since 1978; a substantial increase in groundwater salinity has occurred; and significant over-exploitation of the aquifer has taken place.