Si Environmental (formerly TOPS) serves as a water/ wastewater utility operator for Harris County MUD 537.
Si Environmental, LLC
Attn: Jaison Sanwald
9826 Whithorn Dr.,
Houston, TX 77095
Phone: (281) 807-9500
Email: cyp.customerservice@sienviro.com
Pay Your Bill Online
Additional Payment Options & Service Requests
Mock Bill and Rates for Understanding Your Water Bill
Customer Support
For billing, service requests and other inquiries use the following:
General Customer Service Number: (281) 807-9500
Customer/Billing Inquiries Email: cyp.customerservice@sienviro.com
For general phone inquiries, please contact our Customer Service department Monday through Friday from 8:30 a.m. to 5:00 p.m., with the exception of holidays.
Customer Service/Payment Center Office
9431 Rio Grande Dr.
Houston, TX 77064
Phone: (281) 807-9500
Main Office
6420 Reading Road
Rosenberg, TX 77471
Phone: (832) 490-1600
For after-hour emergencies, please contact our dispatch team at (281) 807-9500.