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Long Term 2 Enhanced Surface Water Treatment Rule

Information regarding the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) Cryptosporidium monitoring for public water systems.


The LT2 Rule requires the start of Round 2 for Cryptosporidium monitoring as the following table shows:

Raw Source Water Monitoring Schedule

Systems that are not part of a combined distribution system(1) and serve . . . must begin the first round of source water monitoring no later than the month beginning . . . and must begin the second round of source water monitoring no later than the month beginning. . .
At least 100,000 people October 1, 2006 April 1, 2015
From 50,000 to 99,999 people April 1, 2007 October 1, 2015
From 10,000 to 49,999 people April 1, 2008 October 1, 2016
Fewer than 10,000 people and monitor for E. coli October 1, 2008 October 1, 2017
Fewer than 10,000 and monitor for Cryptosporidium April 1, 2010 April 1, 2019
(1)Systems that provide treated surface water to another system and are part of a combined distribution system must begin monitoring at the same time as the system in the combined distribution system that has the earliest compliance date.

 For further information on Round 2 of the LT2 Rule please contact:

Tamira Konkin-Garcia at or (512) 239-1758.

You may also try the EPA web link to the LT2 Rule.Exit the TCEQ


ATTENTION: As of February 4, 2010, the EPA has reviewed the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) and issued a memorandum with a new E. coli benchmark level to immediately allow a higher Cryptosporidium trigger level for water systems. The new E. coli benchmark trigger level for Cryptosporidium is an average 100 E. coli colonies/100mL for lakes, reservoirs, and flowing streams. Any public water system that received notice from the TCEQ of exceeding the former E. coli benchmark levels which triggered the mandated Cryptosporidium monitoring possibly may not be required to monitor for Cryptosporidium.



On February 4, 2010, the TCEQ began contacting public water systems to inform each system of its LT2 status based on the new E. coli benchmark from the EPA.


Systems that serve no more than 9,999 people and obtain any portion of their water from a surface or GUI (groundwater under the influence of surface water) source begin sampling October 2008. Sampling has begun for the LT2 Schedule 4 Systems in Texas. These are approximately 225 small water systems — for this rule systems that serve no more than 9,999 people and obtain any portion of their water from a surface source or a GUI (groundwater under the influence of surface water) source.

Beginning October 2008, systems that have chosen to sample for E. coli have begun sampling their source water. As stated in the rule, no acceptance of the plan is needed from TCEQ. Systems may begin sampling on the schedule detailed on their sampling plan. Systems should submit a copy of the sample results from the lab to us along with the below LT2 Raw Surface Water Sampling Form. Please submit your available sampling results for the month and Raw Surface Water Sampling Report with your Surface Water Monthly Operating Report (due by the 10th of the month following the period you are reporting for). Remember you must take your sample within 2 days of the sample date on your sample schedule. Your system is required to attach your Sample Schedule, Source Worksheet and Sample Schematic to your Monitoring Plan. Below are links that you may find helpful;

If you have not submitted your sampling plan, please see below.

Sampling Plan Deadlines

These deadlines relate to new rules for monitoring and controlling Cryptosporidium in your water system:

  • July 1, 2008—By this date, you must tell us in writing how you plan to meet sampling requirements. You have four options:
    1. Submit to us a sampling schedule for E. coli and a description of the sampling location.
    2. Send us a letter stating that you plan to submit grandfathered data.
    3. Send us a letter stating that, instead of sampling, you plan to provide the additional treatment necessary to achieve a 5.5-log inactivation or removal of Cryptosporidium.
    4. Send us a letter stating that you plan to skip E. coli sampling and sample for Cryptosporidium instead.
  • October 1, 2008— By this date, you must implement the plan you submitted in July.

Sampling Requirements

Unless you have submitted grandfathered data, are providing full treatment, or are sampling for Cryptosporidium, in October 2008 you must begin sampling every surface water or GUI source as follows:

  • Sample for E. coli every 2 weeks for a year (a total of 26 sampling events).
  • In each of these sampling events, E. coli must be enumerated. In other words, colonies must be counted; “presence/absence” results are not sufficient.
  • All E. coli samples must be analyzed by a TCEQ-accredited laboratory.

Materials to Help You Meet These Deadlines

In May, we mailed each of the 225 systems in Schedule 4 these materials to help them provide the required information to us. If you did not receive your package or would like these materials in electronic format, please use these files (help with PDF files):

Rules for These Deadlines

The federal LT2ESWT Rule Exit the TCEQ was published in the Federal Register January 5, 2006. The Texas version of this rule, Title 30 Texas Administrative Code Chapter 290 Exit the TCEQ, was published in the Texas Register January 4, 2008, and took effect January 9, 2008.

Purpose of These Rules

The goal of the new LT2 is to reduce the risk of disease caused by Cryptosporidium and other microorganisms by identifying the systems with the greatest potential for source water contamination.

The EPA finalized both the LT2 and the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) at the same time. Together, these rules will improve protection against microbial contamination while reducing risks from disinfection byproducts in drinking water.

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