Water Operator

At Si Enviro, we are committed to the satisfaction of you, the customer.  We strive to meet all of your needs when it comes to the most precious resource on the planet: WATER.


View or Pay Water Bill

If you would like to review your invoice, check your balance or even pay your bill online (where applicable), please visit https://www.eonlinebill.com/bapp/sienv/wp01.r.

Keep in mind that delinquent payments made online could take 24 hours to process and do not guarantee immediate reinstatement of service once disconnected.

InstaPay with our new QR Code

You may have seen this strange looking box on your invoices for your water usage.  This is our new QR Code (Quick Response Code) that allows you to quickly pay your water bill by simply using your mobile device.  Just download a free QR Scanner for your mobile phone (available in your device’s app store) and scan this code.  Once scanned, you may quickly assess your account information, enter your credit card information (and soon, even enter your checking account for direct debit), chose to use this payment method for future bill payment (OPTIONAL) and click Pay Bill.  That’s it!  It generally takes less than 2 minutes and your bill is paid.

Less time, less hassle, less check writing.  More time and freedom from bill paying hassles.  Try it!  We think that you will love it!

Questions About Your Bill

If you have a question about your water bill or service problems, please call Si Environmental at (832) 490-1600, Monday through Friday, 8 a.m. to 4 p.m., or email CustomerCare@SIEnv.com.  For service problems after hours or on weekends, call (832) 490-1601.

Report an Emergency

Please call us immediately at (832) 490-1601 (Local) or 1 (877) 382-7416 (Toll Free) if you have an emergency to report, such as:

  • Water Leak
  • Loss of Pressure
  • Service Interruption
  • Water Main Break in your Area
  • Sanitary Sewer Stoppage
  • Public Health Hazard

Water Rates

The following rates are effective November 16, 2015.  The cost of your service is based on consumption, with a minimum monthly charge.  This covers the cost of water transmission, treatment, and distribution.  Charges are also based on meter size and covers the cost of meter reading and billing, customer service, meter replacement and repair, system capacity, water conservation, and administration.  Billed amounts are based on meter readings for the previous month.

Usage (gal.)
Rate/1,000 gal.
Over Minimum
Levels (gal.)
10,001 to 20,000
20,001 to 30,000
over 30,000
North Lake Village
Cornerstone Place
over 30,000
over 30,000
All others
over 30,000


In addition to the foregoing rates, the Consumer shall pay a North Fort Bend Water Authority Fee per thousand gallons, equal to the pumpage fees per thousand gallons of water that the District is required to pay, if any, to the North Fort Bend Water Authority with respect to water that is delivered to the Consumer. Note: The information provided above is a summary of the District’s services and rates (based on residential 3/4″ meter), which are qualified in their entirety in the District’s complete statement of its rates, rules and policies, and by local, state and federal regulations, and are subject to change without notice.

Tax Rates

5-Year Tax Rate History
2011 – $0.17   + 0.19
2012 – $0.165 + 0.195
2013 – $0.165 + 0.195
2014 – $0.15   + 0.19
2015 – $0.13   + 0.20
2016 – $0.125   + 0.175

Regional Water Authority

Cornerstones MUD participates in a regional water authority (RWA) whose mission is to reduce the use of well/ground water and increase the use of surface water. Reducing dependence on well water leads to a reduction in ground subsidence as required by Texas state law. Districts are required to reduce ground water usage by 30% by December 2013, the current plan is for Cornerstones MUD to convert to surface water no later than 2025. The North Fort Bend Water Authority (NFBWA) was created in 2005 to allow well owners like Cornerstones MUD to band together to mutually accomplish this mission. The NFBWA borrowed $300 million to finance water pipeline construction that extended from the City of Houston to northern Ft. Bend county. This water pipeline currently provides surface water to approximately 30 MUD’s inside the NFBWA footprint. By over-conversion to surface water in those Districts, the remaining Districts in the NFBWA footprint can continue to use ground water until the next required reduction no later than 2024.

The RWA fee included on your monthly invoice provides for re-payment of the borrowed funds and ongoing operations of the Authority. The NFBWA increased that fee from $2.70 per 1,000 gallons used to $3.05 per 1,000 gallons used effective January 1, 2017. Cornerstones MUD’s rate order required that this fee be passed through to you the consumer at cost. This fee is expected in increase annually as NFBWA is planning to borrow more funds to build additional water infrastructure.

SI Environmental handles all billing and payments for Cornerstones MUD.

Summary of Water Conservation, Drought & Emergency Contingency Plan

The District’s Fourth Amended Drought Contingency Plan was adopted on November 19, 2012, for times of severe shortage of rainfall and decreased water supply, and to ensure that adequate supplies of water are maintained in the District.  During such times, the District will distribute information to its residents and other users of water regarding water conservation.

In general, drought conditions are reached when the water supply reaches 80% of the District’s production capacity for three consecutive days.  During such times, the following measures are taken:

  1. The District will inform water users of the drought conditions, and any restrictions on water use by notices and press releases.
  2. During mild drought conditions (75% capacity), the District will recommend that users voluntarily reduce water use.  Outdoor water use (lawn watering, car washing, etc.) will be limited as follows: even-numbered addresses may use water outdoors only on Wednesdays and Sundays and odd-numbered addresses may use water outdoors only on Tuesdays and Saturdays.  Outdoor water use shall be prohibited between the hours of 7:00 a.m. and 10:00 a.m., and between the hours of 6:00 p.m. and 10:00 p.m.
  3. During moderate drought conditions (85% capacity), in addition to the above requirements, outdoor water use may be conducted with a hand-held hose only.  The District will also recommend that non-essential water usage such as the filling of swimming pools and street washing be curtailed.
  4. During severe drought conditions (90% capacity), outdoor water use will be prohibited, a surcharge will be applied on water use in excess of 10,000 gallons per month, and in emergency situations the District may prohibit water use not essential to health and safety related uses, and impose penalties for violation of emergency response measures.  These penalties may include written notification for the first violation, and monetary penalties and discontinuation of service for subsequent violations.  Variances may also be granted for emergency conditions affecting health, sanitation and fire protection.

The above summary is provided for information purposes only.  For a complete understanding, please click here for the complete Drought Contingency Plan.