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Water Treatment to Control Pipe Corrosion

The EPA requires monitoring for the presence of lead and copper with the goal to minimize human exposure to lead and copper in drinking water. Neither lead nor copper has been detected in Renton's water sources. However, our water is naturally corrosive and could cause lead and/or copper present in home plumbing to leach into drinking water.

In 1993, the City of Renton tested for the presence of lead and copper in water drawn from 75 household taps. None of the tested taps exceeded the EPA's action level for lead of 15 parts per billion. However, 63 of 75 tested tap samples exceeded the EPA's action level for copper of 1.3 parts per million. To remedy this situation and comply with EPA regulations, the City of Renton constructed the Corrosion Control Treatment Facilities in 1998 and started the operation of the facilities in the spring of 1999. The treatment process entails adding sodium hydroxide to the water to raise the pH from below 7.0 to above 7.3. At this higher pH, the water is less corrosive to household plumbing, which in turn, reduces the leaching of lead or copper from home plumbing.

In the fall of 1999, the City retested for lead and copper at 72 of the previous 75 household taps. None of these tested taps exceeded the EPA's action levels for lead or copper. Our water now meets the EPA's regulations for lead and copper.

If you have any questions concerning this water treatment procedure, please contact Abdoul Gafour, Water Utility Manager, at 425.430.7210 or by email using the link below.

Email Water Utility Manager