The following response is provided on behalf of both the City of Guelph Waterworks Division and Wellington-Dufferin-Guelph Public Health. Please contact either agency as outlined below if you require additional information.
Some communities with unique water quality characteristics, including London, are finding elevated levels of lead in water samples taken from customers’ taps. In some cases, these results are above the Provincial drinking water health related standard and are occurring in water sampled from homes with lead water services (the ‘water service’ is the dedicated pipe that carries water from the watermain in the street into a customer’s residence). This unique water quality may cause lead to dissolve from lead water services, fittings, and solder into tap water. In response, London, in consultation with the provincial Ministry of the Environment (MOE) and the local Health Unit, is implementing customer education programs, performing additional monitoring, and enacting lead service replacement programs.
The presence of lead in municipal drinking water is regulated by the MOE. Provincial regulation requires annual lead testing in the water distribution system and sets a health related drinking water standard of less than 10 micrograms per litre (ug/L), equivalent to 10 parts per billion (ppb). Drinking water standards are established by the MOE based on medical research and consultation with Health Canada.
Over the last twenty years, both Guelph Waterworks (Waterworks) and Wellington-Dufferin-Guelph Health (WDGPH) have been monitoring Guelph’s drinking water for the presence of lead. These results have been reviewed by the MOE and WDGPH, and are summarized in Waterworks Annual Reports. The vast majority of sample results show levels to be approximately one tenth of the standard, with a rare result approaching the standard. In any water quality monitoring program, a rare high result is not unusual and may be attributed to sampling conditions and/or analytical techniques.
Monitoring results indicate that Guelph’s groundwater sources have little or no naturally occurring lead with levels much lower than the health related drinking water standard. Furthermore, the characteristics of Guelph’s drinking water (quality) is likely the contributing factor for low lead levels in Guelph municipal tap water.
In the last five years, the average lead content found in samples taken from Guelph’s water distribution system is 1.3 ug/L. There were no comfirmed samples in excess of the 10 ug/L standard .
Since 1991, in conjunction with the MOE, Waterworks has been monitoring the average lead content in tap water from homes in Guelph where the plumbing may contain lead solder. The average lead content of these samples is approximately 0.93 ug/L with a one-time high result from one home of 13 ugL. Prior and post sampling results from this same home were consistently below the guideline.
It was common building practice in Guelph and surrounding areas for lead water services to be installed on municipal and private property until the mid-1950s. The standard practice of using lead to seal watermain joints was phased out in the early 1970s. Since 1990, the use of lead based solder has been prohibited under the provincial plumbing code. The use of lead based piping and fittings are also prohibited under current provincial drinking water legislation. Before purchase and installation, Waterworks and Engineering Services review the composition of all pipes and fittings to ensure compliance with provincial requirements related to lead composition.
Although a large number of lead services have already been replaced in Guelph and other communities, a small number of lead water services may still remain in use. Over the last fifteen years Waterworks has proactively replaced identified lead services with copper on municipal property, and has encouraged private property owners to do likewise. Waterworks currently implements an annual water service replacement program that has resulted in the replacement of over 1,000 older services on municipal property over the last twenty years.
Both Waterworks and WDGPH will continue to monitor the drinking water levels issue in Guelph and surrounding municipalities. Waterworks will continue to monitor for the presence of lead in the water supply and distribution systems and in customer tap water to ensure customer safety and regulatory compliance. Waterworks is reviewing historical records to identify the potential locations of lead water services that may still be in use. Action plans are also being developed, in consultation with the WDGPH and MOE, to review sampling programs to ensure that up-to-date and relevant data is available regarding lead concentrations. Furthermore, a joint action plan is also being developed to ensure, based on priority and potential customer impact, the replacement of any municipal lead water services that are identified.