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Well-Klean and California Water Service

Water Well Rehabilitation

Case Study

San Jose, CA

September 2020

California Water Service (Cal Water) is the largest regulated American water utility west of the Mississippi River and the third largest in the country. Formed in 1926, the San Jose-based company serves 489,600 customer connections through 23 districts throughout the state. Cal Water is the largest subsidiary of the California Water Service Group, which also includes Washington Water Service, New Mexico Water Service, Hawaii Water Service, HWS Utility Services, and CWS Utility Services. As a whole, the Group provides high-quality regulated and non-regulated utility services to approximately 2 million people in 100 communities.

After the initial brushing with a mud remover product and bailing, Well-Klean from HCT was asked to review and make recommendations.

Well Dynamics:

Potable Water Extraction Well Off-line 4 years. 19 years of age. Casing is 16 inch louvered copper bearing steel.

Standing water level 42 ft. Total Depth 710 ft. Fill in casing 9 ft. LSI Value – slightly scaling (0.6)

Unique Properties: Lined

Well-Klean©, NSF 60 Products:

1,021 Gallons - WaterSOLV BC 1,060 Gallons - Well Klean Pre-Blend

500 lbs - Sodium Bicarbonate


  1. We choose to clean the entire well as it "appears" to contain calcium phosphate from SWL to total depth. CaPO4 will support bacteria as well as promote bacteria growth and colonization of the well.

  2. Based on the ground water LSI, this water is moderately scaling, though LSI does not incorporate the PO4 in its equation. The ground water is actually very scaling with the PO4 presence. The silica is high but not a concern as the CaPO4 has likely kept it sequestered, free form forming silicate scale (glass in a sense). Sulfate, Iron and Manganese played a minor role, as we would assume the bacteria had preference on the phosphate.

  3. The CITM scan exhibited concerns at blank casing intervals of 390 to 405, and also 500 to 505. These should be collectively reviewed, discussed and decisions documented to mitigate any casing damage.

  4. If this well sits stagnant for more than a few days after remediation, it should be saturated with layup chemistry containing sodium bicarbonate and HCT's WaterSOLV™ BC. Adequate flushing to waste would be required by NSF 60 Standards prior to placing the well back online.

  5. This well will require bio and CaPO4 remediation perhaps once every 1-2 years. This can be accomplished insitu, pump in place, by assuring the well check valve can be manipulated open so that surging the well can be performed (rawhiding).

HCT is the first and only company to bring forward a bio-remediation solution for effective well cleaning. We have treated over 900 wells (9/2023), mostly all were municipal potable drinking water wells. Every well is unique, and most wells require bio-remediation versus descaling, and physical energy as possible while protecting the integrity of the structure.

Most wells get sick at about 14 years of age and present performance issues. Through our unique testing criteria, we can determine whether the well is likely sick from biology or scale, or perhaps leaning towards one side or the other. Perhaps the worst things you can do to your well are brushing it without the presence of adequate biocide or disinfection as the bacteria are then spread throughout the well. Trying to clean a well with some form of chlorine which is a minor, temporary solution, is ill advised as chlorine is significantly corrosive, not a cleaner, but a disinfectant.

We offer a very powerful, aggressive and effective program for the remediation, and in some cases, restoration, of water wells. Our program focuses on synergy between chemistry, processes and procedures, that yield the optimum and longest lasting results.



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