what is a cusi
About CUSI CUSI is dedicated to providing innovative enterprise solutions to utility companies. Over 30 years of industry experience and commitment to client services. One of the nationâs largest providers of utility billing and customer information systems. 1  1,100 utility companies use CUSIâs solutions to manage water, sewer, gas, electric and waste utilities. 2  CUSI services utility companies with customer bases ranging from less to 500 to over 150,000 customers.