This flow chart describes the steps of a protocol used to undertake initial monitoring for lead concentrations in drinking water in non-residential sites. A two-tier protocol is depicted by boxes connected by one-way arrows to guide the user through the process. The user proceeds through the protocol based upon the analytical results received for lead.

The first box provides instructions on collecting the first set of samples. This box is entitled Tier 1: Lead Concentration and samples are to be collected only after the water has remained stagnant in the pipes for a minimum of eight hours, but less than twenty-four hours. A 250 mL sample is collected and submitted for analysis.

A one way arrow leads to the second box in the main branch of the flow chart which states that if any of the samples yield a lead concentration greater than 0.020 mg/L, the user should proceed along the same branch of the flow chart to the third box which states that corrective measures should be implemented and additional sampling conducted. This sampling is then described in the fourth box in this main branch of the flow chart entitled Tier 2: Lead Concentrations which instructs the user to flush the taps for thirty seconds, collect a 250 mL sample after the water has remained stagnant in the pipes for a minimum of eight hours but less than twenty-four hours, and then submit the sample for analysis. If none of the samples from Tier 1 yields a lead concentration over 0.020 mg/L, no action is required.

A one way arrow leads to the fifth box in the main branch of the flow chart which states that if none of the samples in Tier 2 yields a lead concentration greater than 0.020 mg/L, the user is directed, by a one way arrow, to a box on the right side of the flow chart indicating that the source of the lead is the outlet. If, however, any of the sample results from Tier 2 shows a lead concentration greater than 0.020 mg/L, a one way arrow directs the user to the sixth box in the main branch of the flow chart which indicates that corrective measures should be implemented and additional sampling should be conducted.

The final one way arrow then leads to the seventh box of the flow chart instructing the user to proceed in determining the source of lead.