Water Quality Monitoring

Public water systems using surface water sources must monitor regularly for turbidity and chlorine residual to ensure that they are treating effectively for pathogenic organisms. While the measurement methods are relatively simple, proper measurement technique is vital. The following measurement guides are deigned to cover common pitfalls and sampler errors that result in inaccurate measurements. The troubleshooting tables at the ends of the documents describe the most common reasons for noncompliant monitoring values and how to resolve them.

• Chlorine Residual Measurement Guide (PDF)
• Turbidity Measurement Guide (PDF)

Small noncommunity public water systems using surface water sources must collect a total coliform sample each month to ensure the bacteriological quality of the water served. These samples must be collected from the distribution (e.g., at a kitchen sink). A chlorine residual measurement must be taken from the sampling location prior to filling the bottle (different than the daily chlorine residual measurement collected at the entry point). If there is no chlorine residual detected at the sampling location, the tap should be flushed until a residual is detected.

• Total Coliform Bacteria Sample Collection Procedure (PDF)
• Total Coliform Bacteria Sample Collection Procedure (Video)