July 1, 2022: The Centers for Disease Control and Prevention has listed Fairfield, Hartford, New London, Tolland, and Windham Counties in Low/Green the as part of its COVID-19 Community Levels Map. Only Litchfield, Middlesex and New Haven Counties are listed in the Medium/Yellow category. Residents who live in the Medium /Yellow counties who are at a high risk for severe illness, should talk to their health care provider about whether to wear a mask and take other precautions. These residents should stay up to date with their COVID-19 vaccines and get tested if they have symptoms. Visit the CDC COVID-19 Community Levels Map for updates.

CT Department of Public Health, Environmental Health Section; finalized September 2017

Private Well Contamination Coordination Protocol

This protocol outlines generic responses that the Connecticut Department of Public Health (DPH) can initiate in the event of the discovery of one or more private wells with elevated levels of manmade or natural contaminants. Much of this response is not under the direct control of DPH, so this protocol generally contains suggested actions by a number of governmental agencies and private individuals. The Connecticut Department of Energy & Environmental Protection (DEEP) maintains primary responsibility to investigate cases where private wells may be at risk of becoming contaminated or have been contaminated as a result of manmade sources of pollution and to identify the party(ies) responsible for the pollution. DEEP does not investigate cases of naturally-occurring pollution, except in cases where such contamination is mobilized by manmade activity. Recommendations are provided below for coordination between the DEEP, the DPH and local health departments (LHD). This protocol is not intended to limit a LHD’s discretion to respond to any water quality test result at any level of detection.  

Naturally Occurring Contaminants

Introduction:  The finding of naturally occurring chemicals in private well water in a particular location can take a number of paths for investigation and resolution. No one agency has been delegated authority over this topic, but in general DEEP programs will not follow up on naturally occurring chemicals in groundwater. Therefore, it is up to the LHD and DPH to initiate steps once an area is suspected of having private wells at risk from naturally occurring chemicals, such as but not limited to, arsenic, uranium, radium, fluoride and radon. Manganese may also be naturally elevated but its migration to a well may be influenced by human activities and could therefore fall under either DEEP or LHD/DPH responsibility. The naturally occurring parameters identified in this section are those that have been found in Connecticut and can be considered toxic at high levels. Local Health Departments are encouraged to contact the DPH Private Well (PW) Program when any other naturally occurring parameters are detected at abnormally high values.  

1. Critical Response Screening Levels: When a LHD or DEEP becomes aware of a single well with a significantly elevated level of a natural chemical in well water, they should contact the DPH PW program and inform them of the result. For the purposes of this protocol, a significant1 elevation means (and is not limited to):

  • Arsenic > 100 ppb
  • Uranium > 900 ppb
  • Radium > 150 pCi/l
  • Fluoride > 3.5 ppm
  • Manganese > 300 ppb
  • Radon > 40,000 pCi/L

1Significant levels for arsenic, uranium and radium are based on the CT DPH Bathing and Showering Guidance for Private Wells (see appendix). 

The list of contaminants with respective elevated levels above, are not intended to limit a LHD’s discretion to respond to any water quality test result at any level of detection, but rather provide general guidance on when action should be taken.  

The DPH PW program will then discuss follow-up options with the LHD, as described below. 

2. Whenever the LHD or the DPH PW program become aware of any single well that is “significantly” elevated or when two or more wells in close proximity are over an MCL or action level, then the discovering agency will notify the other agency. The DPH PW program will consult with the LHD to discuss response options. The DPH PW program may also notify DEEP if DPH or the LHD have reason to believe these conditions are the result of surrounding land use or other manmade sources of pollution.

The response options may include:

  • The LHD will inform nearby neighbors about the elevated result and suggest they hire a private lab to test their well for the chemical in question. 
  • The LHD may initiate sampling of wells in the vicinity and submit samples to the DPH lab. The LHD may consult with the DPH PW program on the number of samples to be taken and how far from the index well such testing should occur. 
  • The town government may issue general information to its citizens with private wells that the chemical in question may be a problem and encourage testing.

3. If testing undertaken by the LHD reveals more wells with elevated levels in the area of the index well, then consideration should be given to:

  • Expanding the area of testing;
  • Expanding the area where well owners are notified;
  • Consulting with the United States Geological Survey (USGS) or the CT State Geologist to consider geology;
  • Informing the entire town and recommending all private wells be tested through a private lab; and
  • If elevations in a town are very widespread, then a town ordinance requiring testing for new wells should be considered.

4. Private labs are required to report testing data to the LHD and DPH when the test was conducted in connection with the sale of a property, no later than thirty days after the completion of the test. This data should be reviewed regularly by DPH and the LHD to see if
any elevations in naturally occurring chemicals have been documented. Private labs should be encouraged to alert LHDs and DPH when wells with significantly elevated test results are identified.

5. If elevated levels of naturally occurring chemicals are documented over a wide area of a town, then the DPH PW program will consult with the State Geologist and/or the United States Geological Survey (USGS) to get an understanding of the underlying bedrock and its
possible correlation to the elevated findings. If a suspected bedrock type extends into neighboring towns, the DPH PW program will notify those towns for possible follow up.

6. The DPH PW program will keep a database with all reported elevations for future analysis and reference.

Man Made Contaminants:

Introduction: Manmade contaminants may often be detected when sampling a water supply well. When they do not exceed health criteria, they may warrant further evaluation or monitoring, but additional actions are necessary to protect human receptors when criteria are exceeded. The LHD is typically the lead for problems of bacterial contamination, and may also assume the lead for contamination originating with on-site septic systems, such as nitrates. DEEP’s Sub-surface Disposal and Agriculture program may also be involved in evaluation of these issues if associated with an activity under their jurisdiction. For most other manmade contaminants, the DEEP Remediation Division is involved.

1. Whenever private well sampling results are above federal or state maximum contaminant levels (MCL) or action levels, the agency receiving the results first should notify the other two agencies. The initial agency of discovery may seek additional information to substantiate the report before referral to the other two agencies.

2. If the LHD conducts any further investigations of manmade contaminants, they may use the general approach outlined in 2 and 3 above for progressive expansion of the study area. If this sampling identifies the source of the contamination, they should notify the owner of that property under the provisions of CGS 22a-6u (b) or (c).

3. In the absence of a viable responsible party conducting an investigation, DEEP will often be the lead in investigating sources of manmade pollution, including sampling of other nearby wells. DEEP will coordinate with the LHD on who will be collecting additional samples. Agency-obtained sampling results should be shared with the other agency. Reports of results sent to DEEP, but obtained by responsible parties sampling under DEEP’s Remediation Programs (i.e., Significant Environmental Hazard Program, Potable Water Program, Pollution Abatement Order, Water Supply Order, etc.) will be shared with the LHD as they may request. However, if these results include exceedances of criteria, follow approach in 4 below. Also, if DEEP identifies the source of the pollution, they will inform the LHD. If the contamination impacts three or more private wells above established criteria, the DPH PW program will be informed of DEEP’s investigation results.

4. If testing of a private supply well by a responsible party is ordered by DEEP and identifies contaminants elevated above MCLs or Action Levels, the responsible party must notify the owner of the well, DEEP, DPH, and the LHD within 24 hours. In addition, if not an owner occupied dwelling, the well (property) owner must notify each lessee and one tenant in each rental unit within 24 hours. The LHD is required to verify within 3 days that this notification by the owner has been made. [Reference CGS 22a-6u (i)] If testing is done by DEEP or the LHD, a similar notification to well owners and occupants of rental units should be made.

5. The LHD or DEEP can contact the DPH Private Well (PW) Program if there are questions about relevant treatment technologies and the extent of the problem. If there are health concerns among the residents impacted, the DEEP will refer citizens to the DPH
Environmental and Occupational Health Program, which will then coordinate health messaging with the LHD. When necessary, DEEP will also coordinate with DPH’s Drinking Water Section about the potential to connect affected homes with private wells to public
water supplies if such supplies are nearby.

All well owners with elevated test results should be referred to the DPH PW program to discuss relevant treatment technologies.

Appendix Materials:
CT DPH: Action Level List for Private Wells
CT DPH: Bathing and Showering Guidance for Private Wells