The City of Ripon has a need for non-potable water.

This is water not suitable for drinking but useful for irrigating outdoor landscape or non-functional turf.

The Ripon City Council touched on that during last week’s special session while adopting the emergency water conservation measures.

Included are possible linkups to non-potable water to places with non-functional turf. More on that is expected to take place at the July meeting.

No discussion was necessary Tuesday as elected leaders approved an amendment to the service agreement with Wood Rodgers, Inc. – signed initially in 2017 to provide a hydrogeologic assessment to determine whether the operation of Well 12 would have a mitigation impact on the nitrate plume – for additional work in preparing the operation and monitoring plan along with the test and sampling to operate Well 12, as requested by the State Regional Water Quality Control Board.

The cost was not to exceed $25,761 from the Water Enterprise Operating Fund.

Well 12, which was part of the rehabilitation project that also included Well 5, was completely modified to completely seal off the upper aquifer, eliminating the contamination of nitrates in the well and lower aquifer, according Public Works Director James Pease in his report.

He noted that the City’s drinking water is obtained from these lower aquifers, offering clean water that meets the State’s drinking water standards.

“Although post testing has shown a decrease in nitrates to Well 12 since the modification was completed, the levels are still not suitable to use the well for potable drinking water,” Pease added.

The Regional Water Quality Control Board’s earlier request on a monitoring and reporting plan on the well confirmed that pumping does not impact the nitrate plume.

In March 2020, the Well 12 pumping operation began for use in the City’s non-potable system, providing somewhere between 500 and 750 gallons per minutes when activated since that time.

The pumping rate and analytical results, as monitored by Wood Rodgers, Inc., went through several revisions prior to approval by the Regional Water Quality Control Board, with an additional cycle testing and water quality sampling of the past two years resulting in an increased cost incurred by the Sacramento-based engineering firm.

City staff will be working with the Regional Water Quality Control Board to determine the required path necessary in order to continue pumping Well 12 beyond 2022.