Site Remediation

Requirements for Monitoring Well Installation:

  • A permit application is required to install or abandon a monitoring well and install soil borings.
  • All monitoring wells/soil boring/exploratory boring installations shall conform with existing California Well Standards for construction and construction materials.
  • Prior to drilling, a line-locating service shall be used to identify any potential drilling obstructions.
  • All equipment, drill cuttings, and well development water shall be temporarily contained in Department of Transportation (DOT) approved drums on site until lab analysis is complete. Drums shall be properly labeled and dated. Temporary storage time shall not exceed 90 days.
  • Monitoring wells must be completed at least 12" above grade with a monument type protection cover. Flush type vaults shall be used in traffic areas only.
  • Each monitoring well must be locked and numbered.
  • All equipment used in drilling and sampling activities must be properly cleaned before and between each use. Chemicals, glues and solvents shall not be used in the construction of monitoring wells/soil borings.
  • If the site is not ready for a scheduled inspection appointment, then an additional hourly Department fee may be charged.
  • An annual permit fee may be charged, and an annual inspection may be conducted to confirm the status of the monitoring well.
  • Other requirements may apply at the discretion of this Department. Contact this Department at (530) 621-5300 in Placerville or (530) 573-3450 in South Lake Tahoe for further information.
  • Contact this agency to schedule a final inspection with a minimum of 48 hours advance notification.

Requirements for Groundwater Monitoring and Sampling (M&S)

The El Dorado County Environmental Management Department maintains oversight of groundwater sampling performed at contaminated sites within the county. Please be advised that the El Dorado County Environmental Management Department (EMD) now requires the following:

  • At least one week notice of upcoming groundwater sampling at contaminated sites prior to the date of the M&S event.
  • An SOP-type document included in your M&S reports that specifically describes how your groundwater monitoring and sampling activities will be (or were) performed at each site.
  • Provide proof of completion of 40-hr HAZ-MAT and Emergency Response training required and should be available for inspection by county personnel (29 CFR 1910.120).
  • A site-specific and activity-specific Health and Safety Plan and kept in a prominent location at the site during field activities. The Health and Safety Plan should be prepared in accordance with California Code of Regulations Title 8, Section 5192, Part 4, Section (B).
  • Please check back for additional site assessment and remediation information, which will be posted as it becomes available.

Requirements for Destroying Monitoring Wells and Soil Borings:

A well is considered abandoned or permanently inactive if it has been unused for more than one year. Abandoned or permanently inactive wells must be destroyed in accordance with all relevant sections of CA Water Code Division 7, Chapter 10, CA Health and Safety Code Division 104 Part 9.5, and CA Water Well Standards Bulletins 74-81 and 74-90, including the following:

  • Prior to destroying a well, it must be investigated to determine the construction details, maintenance history and current condition. A work plan including the investigation findings and destruction method must accompany the permit application.
  • Wells must be sounded immediately prior to destruction to ensure they are free of obstructions. If any chemical contaminants are observed, Environmental Management Department must be immediately notified in writing. Wells shall be cleaned to remove and properly dispose of all obstructions and contaminants.
  • For wells constructed and maintained in accordance with CA standards, casing that is more than 5 feet below ground surface may be left in place. The casing must be filled with sealing material up to 5 feet below ground surface. After sealing material has set, a 5-foot-deep hole shall be excavated around the casing and the casing cut off at the bottom of the hole. The excavation shall then be filled with clean native soil.
  • For wells not constructed and maintained in accordance with CA standards, all material within the original borehole (annular seal, casing, screen, filter pack, etc.) must be removed. The borehole must be completely filled with impervious sealing material.
  • Acceptable sealing materials include neat cement, sand-cement grout, or concrete.
  • Sealing material shall be placed by “tremmie” pipe or equivalent method in one continuous operation. Sealing pressure must be maintained until sealing materials are properly set.
  • Sealing material may be placed by free fall method only if the well is dry, less than 30 feet deep and does not result in bridging or voids. Volume/fill calculation must be completed to document successful destruction.
  • Soil borings must be completely filled with sealing material up to five (5) feet below grade. Sealing material may be placed by free fall method only if the boring is dry, less than 30 feet deep and does not result in bridging or voids. Volume/fill calculation must be completed to document successful destruction.


  • Monitoring Well = Monitoring wells are different in nature from other wells. They are usually designed to have a shorter life span than other wells, such as water wells. Monitoring wells are usually used in monitoring potentially contaminated sites. These wells are almost always associated with an investigation or clean-up of a potentially hazardous material.  Sites suspected of being contaminated with hazardous materials/wastes must be investigated to determine the lateral and vertical extent of any contamination. Sites found to be contaminated must be remediated. Site investigations and remediations typically include the collection of soil and water samples for laboratory analysis. Subsurface water and soil samples are collected via monitoring wells and soil borings.
  • Soil Boring = A soil boring is an uncased artificial excavation constructed by any method for the purpose of obtaining information on subsurface conditions or for the purpose of determining the presence or extent of contamination in subsurface soils or groundwater and for seismic information.
    El Dorado County Ordinance Code Section 8.38.040 states, "Any person who installs soil borings and/or monitoring wells, conducts a site investigation, or performs off-site or on-site remediation shall obtain and keep current a permit from the Environmental Management Department." To obtain a permit an applicant must submit an application, work plan, site map and permit fees. For projects requiring staff time beyond the hours covered by the permit, additional oversight fees will accrue at the approved hourly rate.