The company operates a total of ten water schemes that provide water to residents of kisii and nyamira county. The schemes are as below.
Ogembo water treatment works with a capacity of 600m3/day draws raw water from the Gucha River. It was constructed in 1990s. the Ogembo town also receives water from the Mosora springs gravity schemes which deliver 600m3/day from Mosora area of Nyamache sub-county in Kisii county.
Suneka sewage treatment plant was constructed in 1994 and treats at least 1500m3/day of wastewater drawn from Kisii town and its environs. Since there is no other full sewage treatment plant in the whole of Kisii and Nyamira Counties other than Suneka. It has become common for individuals and institutions to exhaust their septic tanks and subsequently discharged into GWASCO sewer systems under the watchful eye of the GWASCO staff. GWASCO has an exhauster service vehicle which is hired at affordable prices to provide exhauster services.