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Water Line Inventory

History

The Safe Drinking Water Act was amended, in 1986 by Congress, to stop the use of lead pipes or pipes containing lead in public water systems or plumbing facilities used for human consumption. This was bolstered in 1996 when Congress amended the act again, including a provision that prohibited the use of plumbing fittings and fixtures that contained lead.

On January 15 th , 2021 the Lead and Copper Rule Revisions required public water systems to inventory lead services lines and report the results of the completed inventory by October 16, 2024. This ruling went into effect on December 16th, 2021. As a result, the City of Port Townsend has conducted a review of the water lines managed by the City.

Figure 1. Photo of non lead galvanized water line unearthed during survey.


Methods

Overview: The process of identifying water line material consisted of three steps : 1.) identifying potential locations with lead lines and randomly sampling a subset of those locations using tabular data, statistical software, and GIS (geographic information systems); 2.) Completing field surveys to determine if lead piping exists at potential locations; 3.) Compiling results from the two previous steps and submitting the results to the Washington Department of Health.   

Identifying potential locations with lead lines: The approach developed by the City of Port Townsend (the City) was based on two documents provided by the Washington Department of Health titled “Statistical Guidance for Group A PWS Evaluation of Unknown Service Lines” and “Lead Service Line Inventory Guidance.” These documents identified key factors that allowed the City to develop a feasible methodology to comply with the service line inventory requirements of the Lead and Copper Revisions.

The city used R statistical software (Version RStudio 2024.04.1), Microsoft Excel, and ArcGIS Pro (Version 3.2) to complete step 1. In addition, three datasets including two parcel datasets from Jefferson County (parcel data) and one dataset of the existing service line from the City of Port Townsend (service line data) were incorporated into an analysis that identified potential location with lead service lines. 

Figure 2. Bar graph depicting number of home built after1986, before 1987, and homes with unknown building dates within Port Townsend that a serviced with water from the city.

The City identified 5204 properties with active water meters. Of those, 3253 had building that were either built prior to 1987 or the building date data was not available for a specific property (graph above). To achieve the 95 percent confidence interval (required by the EPA) city staff used a “Statistical Guidance for Group A PWS Evaluation of Unknown Service Lines,” and determined 346 properties needed to be randomly sampled from the 3253 properties.

Figure 3. Line graph depicting work effort during the survey, where effort is number of sites/surveys completed per day.


Survey and Findings

The City created an online survey that collects GPS, photos, and tabular data to expedite and streamline the surveying processes. Crews started sampling the randomly sampled locations on August 28th and completed work on October 12, 2024 (graph above). Following the completion of the survey data was compiled, reviewed in a thorough QA/QC process, and submitted to the DOH on October 16, 2024. The graph below depicts the findings from the survey. The primary material used for both city and private service lines was copper, while the secondary and third material was non-lead galvanized and plastic, ranking dependent on city or private ownership.

Figure 4. Bar graph depicting service line material classifications from survey for private and city owned lines.


Summary and Next Steps

No lead services lines or lead fittings were found during the survey. However, the City of Port Townsend will continue to document service line material classifications and expand upon it's existing database during upcoming construction events and when water lines need to be replaced. The map below depicts the service line material classification.

Zoom into to see private and city line material classification from 2024 survey.

Figure 1. Photo of non lead galvanized water line unearthed during survey.

Figure 2. Bar graph depicting number of home built after1986, before 1987, and homes with unknown building dates within Port Townsend that a serviced with water from the city.

Figure 3. Line graph depicting work effort during the survey, where effort is number of sites/surveys completed per day.

Figure 4. Bar graph depicting service line material classifications from survey for private and city owned lines.