In 2010, Markham established a Sewer Use Compliance Program. It focuses on industrial and commercial discharges into the sewer system.

The Sewer Use Compliance Program covers:

• Sampling and monitoring industrial and commercial discharges
  
• Notifying responsible parties of by-law violations
  
• Investigating sewer use complaints
  
• Investigating and repairing damages to City sewers caused by discharge violations
  
• Laying charges after repeat violations
  
• Recovering costs for system repairs through legal action from responsible parties

Waterworks staff sample and test industrial and commercial discharges. If a test result exceeds the by-law limits, the liable party will receive a violation notice from the City. Markham's notice requires the liable party to take the corrective actions within a specified timeframe. Repeat violators may be charged. Any by-law violation that causes damage to the sewer system will be investigated and repaired. The responsible parties will pay for the costs.