DECATUR, Ga. — In the middle of DeKalb County battling a huge water main break, the head of the county's water department announced he would be leaving.

DeKalb County Watershed Director Scott Towler tendered his resignation with the county, effective Tuesday. In his resignation letter, Towler accused DeKalb CEO Michael Thurmond and Deputy COO Ted Rhinehart of repeatedly telling him to break the law, then punishing him for refusing.

"This letter shall serve as notice of my resignation from my position as the Director of Watershed Mangement for DeKalb County," Towler's letter begins. "I have no choice but to resign this position - despite significant impact to my life and my family - because of the ongoing retaliatory actions by you and CEO Michael Thurmond in response to my refusal to violate the law and participate in unlawful activities in the operation of DWM, especially those which are a violation of the County's Consent Decree and Federal and state environmental laws."

One of Towler's missions as watershed director was to clean up all the massive billing errors. Over the years, thousands of customers were overcharged millions of dollars because of old, faulty water meters. Towler was overseeing the county's $1.3 billion upgrade to the aging watershed infrastructure.

Nearly 700,000 customers depended on Towler to get it all right, but he claimed Thurmond and Rhinehart instead took charge of the watershed department and froze him out.

"DeKalb County is paying me to work in the position of Director of DWM [but] I have been stripped of all authority, decision-making and responsibility,” Towler's letter continues.

READ | Scott Towler's resignation letter

In a Wednesday release, Thurmond called Towler a "disgruntled employee" whose statements about county leadership were slanderous. Thurmond said Towler's comments "contradict verifiable and documented progress in addressing long-festering issues with the DeKalb Department of Watershed Management."

Thurmond's release went on to say that Towler's letter didn't identify any specific action he noted as unlawful, but it did refer to the county's consent decree and other federal and state laws, along with referring to current and pending sewer capacity policies.

"The county has been in constant contact and collaboration with both the U.S. Environmental Protection Agency and the Georgia Environmental Protection Division throughout the development of all policies and protocols," Thurmond said. "We are confident that those policies and all actions taken by the County related to the consent decree have been in full compliance with all applicable laws and standards."