System Upgrade & New Billing Information

Dear Valued Customer,

We are pleased to inform you that our software system upgrade is nearly complete. As part of this transition, your water invoice, starting with the September 2025 statement, will feature a new look and new account number.

After the first complete Billing Cycle by Si Enviro, you will be able to view your Billing History, Payment History and Pay Your Bill using your credit card (Visa, MasterCard, Discover or American Express) or electronic check. We provide an online experience that is secure and convenient. More details about these new payment options as well as others are enclosed. We invite you to visit our website at www.sienviro.com.

Please note: For the August 2025 statement due 9/14/2025, you will only be able to make a payment via check or money order brought to one of our offices or mailed to PO BOX 4824 HOUSTON, TX 77210-4824. Please make sure to include the service address or old account number on the check.

Our goal is to make this transition as smooth as possible and to continue delivering the high level of service you expect from Si Environmental.

Enclosed, you will find the Payment Options and How to Read Your Bill inserts.

If you have any questions or concerns regarding the new invoice format or your account, please don't hesitate to reach out to our Customer Care team:

Phone: 281-807-9500
Email: cyp.customerservice@sienviro.com

Thank you for being a valued customer.

Sincerely,
Si Environmental, LLC.

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PAYMENT OPTIONS

Pay-By-Phone (go to www.sienviro.com, find your district, the number is listed there)

• Visa/MasterCard/Discover/American Express (3% Convenience Fee*)
  Posts next business day
• Electronic Check ($1.00 transaction fee*)
  Posts to account next business day

Online Website (go to www.sienviro.com, find your district, click Pay Online)

• Visa/MasterCard/Discover/American Express (3% Convenience Fee*)
  Posts next business day
• Electronic Check ($1.00 transaction fee*)
  Posts to account next business day

Text to Pay (go to www.sienviro.com, find your district, login online to set up payment via your mobile device)

• Visa/MasterCard/Discover/American Express (3% Convenience Fee*)
  Posts next business day
• Electronic Check ($1.00 transaction fee*)
  Posts to account next business day

Monthly Auto-Draft (go to www.sienviro.com, find your district, login online to set up Auto-Draft)

• Visa/MasterCard/Discover/American Express (3% Convenience Fee*)
  Posts to account on the scheduled draft date
• Electronic Check ($1.00 transaction fee*)
  Posts to account on the scheduled draft date
• Please note: customers who opt to sign up for e-billing and auto draft payments paid via electronic check will have the $1.00 transaction fee waived

All Walmart Locations (Check-Free)

• Visa/MasterCard/Discover/American Express (3% Convenience Fee*)
  Posts next business day
• Electronic Check ($1.00 transaction fee*)
  Posts to account next business day

Western Union (QuickPay - various HEB, Kroger and Fiesta stores)

• $1.50 Transaction Fee*
  Posts to account within (2-3) business days

Online Bill-Pay (through your banking institution)

• Please be sure to include your complete 10-digit account number when setting up Online Bill-Pay through your banking institution (ex: 90XXX-XXXXXXXXXX).
• Please be advised that Online Bill-Pay through your banking institution generally involves your bank utilizing a third-party company to create a paper check that is sent to the specified remittance address. Your Municipal Utility District nor Si Environmental, LLC. will have any control over the check creation and the mailing process for this banking institution service.

Remittance address:
HC MUD #537
PO BOX 4824
Houston, TX 77210-4824

All payments received are processed within 1 business day of receipt by Si Environmental, LLC.

MUD Lockbox (Checks sent via the United States Postal Service)

Mailing address:
HC MUD #537
PO BOX 4824
Houston, TX 77210-4824

All payments received are processed within 1 business day of receipt by Si Environmental, LLC.

Operator's Drop Box Locations:

6420 Reading Road
Rosenberg, TX 77471

9431 Rio Grande Dr
Houston, TX 77064

9826 Whithorn Dr
Houston, TX 77095

• NO CASH ACCEPTED (Personal Checks, Cashier's Checks, and Money Orders only)

All payments received are processed within 1 business day of receipt by Si Environmental, LLC.

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