M-Tergitol 7 Agar Base is recommended for selective isolation and identification of injured coliforms from chlorinated water using membrane filter technique. McFeters, Cameron and LeChevallier modified Tergitol 7 Agar to improve its selective and differential properties for the recovery of stressed coliforms from chlorinated water. Tergitol 7 and polyoxyethylene ether W-1 are surface active agents which inhibit growth of gram-positive bacteria as well as swarming of Proteus.