Private well system in Florida. Image: UF/IFAS, C. Wofford
About 2.5 million Floridians rely on private wells for home consumption, which includes water for drinking, cooking, and personal hygiene. Private wells are not regulated by the EPA Clean Water Act, and well users are responsible for ensuring their water is safe to drink.
What should you have your well water tested for?
The Florida Department of Health (FDOH) recommends that well users test their well water once a year for bacteria at a minimum. Another important contaminant to test for is nitrate.
Bacteria: Labs generally test for total coliform (TC) bacteria and fecal coliforms (like E. coli).
Coliform bacteria are a large group of bacteria and most are harmless. But a positive test result indicates that if they are in your water, other pathogens that cause diseases may also be present. They are used as indicator organisms.
Fecal coliform bacteria are a subgroup of coliform bacteria found in human and other warm-blooded animal feces. E. coli are one species and some strains can cause diarrhea, food poisoning and other illnesses.
If your water sample tests positive for only total coliform bacteria or both TC and fecal coliform (E. coli), FDOH recommends your well be disinfected through shock chlorination. You can either hire a well contractor to do this or you can do it yourself. Information for how to shock chlorinate your well can be found at EDIS Private Wells 101: Bacterial Contamination and Shock Chlorination
Take a water sample at the kitchen faucet if this is where you get most of the water that your household consumes. Image: F. Alvarado
Nitrate: The U.S. EPA set the Maximum Contaminant Level (MCL) allowed for nitrate in drinking water at 10 milligrams per liter of water (mg/L). Values above this are a particular concern for infants less than 6 months old because high nitrate levels can cause a type of “blue baby syndrome” (methemoglobinemia), where nitrate interferes with the capacity of hemoglobin in the blood to carry oxygen. It is especially important to test for nitrate if you have a young infant in the home that will be drinking well water or when well water will be used to make formula to feed the infant.
If test results come back above 10 mg/L, never boil nitrate contaminated water as a form of treatment. This will not remove nitrates. Use water from a tested source (bottled water or water from a public supply source) until the problem is addressed. Nitrate in well water can come from multiple sources, including fertilizers, animal waste and/or human sewage, such as from a septic tank.
You should also have your well water tested at any time when:
The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
A new well is drilled or if you have had maintenance done on your existing well
A flood occurred and your well was affected
Remember: Bacteria and nitrate are by no means the only parameters that well water is tested for. Call your local health department to discuss what they recommend you should get the water tested for. FDOH also maintains an excellent website with many resources for private well users which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.
Where can you have your well water tested?
UF/IFAS Extension will be hosting a private well and water quality workshop on April 11 in Blountstown, with a Zoom option. We will cover well and septic system function and maintenance, water testing and how to prepare for hurricane season. We will also offer facilitated water testing. For more information and to register go to our Eventbrite link or you can also register by visiting the Calhoun County Extension Office, (850-674-8323). Last week’s post about the workshop provides more information as well.
In general, many county health departments accept samples for water testing. You can also submit samples to a certified commercial lab near you. Contact your county health department for information about what to have your water tested for. If they don’t offer testing, they often provide the name of certified laboratories near you. Or you can search for FDEP certified laboratories here.
If you have any questions, you can also reach out to me at albertin@ufl.edu or (850)875-7111.
Join us for our upcoming multi-county private well and water quality workshop. As a private well user, you are responsible for ensuring that your water is safe to drink. We will cover how private wells and septic systems work, proper maintenance, steps to help ensure your drinking water is safe to consume and disaster preparedness for this upcoming hurricane season. We will also offer facilitated water testing for bacteria, lead and nitrate.
The workshop will be offered on Thursday, April 11, 2024, from 9:00 am – 11:30 am CST at the Calhoun County Extension Offices, 20816 Central Ave. E, Blountstown. You can also attend virtually via Zoom. Registration is $5.00 per person. Facilitated water screening for total coliform and E. coli bacteria is available at a reduced cost. Please register on Eventbrite, https://JacksonCountyFCS.Eventbrite.com/ or you can also register by visiting the Calhoun County Extension Office, (850-674-8323). This workshop is being presented by UF/IFAS Extension Bay, Calhoun, Holmes, Jackson, and Washington Counties.
For lead and nitrate testing prices and additional details, visit our Eventbrite page or call the Calhoun County Extension Office at 850-674-8323. Pre-registration is encouraged as seating is limited, but as mentioned previously, a virtual option is also available. For persons with disabilities requiring special accommodations, please contact the Extension Office (TDD, via Florida Relay Service, 1-800-955-8771) at least ten working days prior to the class so that proper consideration may be given to the request. UF/IFAS Extension is an Equal Opportunity Institution.
If your private well was damaged or flooded due to hurricane or other heavy storm activity, your well water may not be safe to drink. Well water should not be used for drinking, cooking purposes, making ice, brushing teeth or bathing until it is tested by a certified laboratory for total coliform bacteria and E. coli.
Residents should use bottled, boiled or treated water until their well water has been tested and deemed safe.
Boiling: To make water safe for drinking, cooking or washing, bring it to a rolling boil for at least one minute to kill organisms and then allow it to cool.
Disinfecting with bleach: If boiling isn’t possible, add 1/8 of a teaspoon or about 8 drops of fresh unscented household bleach (4 to 6% active ingredient) per gallon of water. Stir well and let stand for 30 minutes. If the water is cloudy after 30 minutes, repeat the procedure once.
Keep treated or boiled water in a closed container to prevent contamination
Use bottled water for mixing infant formula.
Where can you have your well water tested?
Contact your county health department for information on how to have your well water tested. Image: F. Alvarado Arce
Most county health departments accept water samples for testing. Contact your local department for information about what to have your water tested for (they may recommend more than just bacteria), and how to collect and submit the sample.
You can also submit samples to a certified commercial lab near you. Contact information for commercial laboratories that are certified by the Florida Department of Health are found here: Laboratories certified by FDOH
This site includes county health department labs, commercial labs as well as university labs. You can search by county.
What should you do if your well water sample tests positive for bacteria?
The Florida Department of Health recommends well disinfection if water samples test positive for total coliform bacteria or for both total coliform and E. coli, a type of fecal coliform bacteria.
You can hire a local licensed well operator to disinfect your well, or if you feel comfortable, you can shock chlorinate the well yourself.
You can find information on how to shock chlorinate your well at:
Texas A&M’s AgriLife Extension Service also provides detailed instructions on shock chlorination in both English and Spanish: Shock chlorination brochure in English and Spanish
After well disinfection, you need to have your well water re-tested to make sure it is safe to use. If it tests positive again for total coliform bacteria or both total coliform and E. coli call a licensed well operator to have the well inspected to get to the root of the problem.
Well pump and electrical system care
If the pump and/or electrical system have been underwater and are not designed to be used underwater, do not turn on the pump. There is a potential for electrical shock or damage to the well or pump. Stay away from the well pump while flooded to avoid electric shock.
Once the floodwaters have receded and the pump and electrical system have dried, a qualified electrician, well operator/driller or pump installer should check the wiring system and other well components.
Remember: You should have your well water tested at any time when:
A flood occurred and your well was affected
The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water.
A new well is drilled or if you have had maintenance done on your existing well
There has been any type of chemical spill (pesticides, fuel, etc.) into or near your well
The Florida Department of Health maintains an excellent website with many resources for private well users: FDOH Private Well Testing and other Reosurces which includes information on potential contaminants and how to maintain your well to ensure the quality of your well water.
Flooding along the South Prong of the Black Creek River in Clay County on September 13, 2017. Photo credit: Tim Donovan, Florida Fish and Wildlife Conservation Commission (FWC).
As hurricane season is upon us again, I wanted to share the results of work that UF/IFAS Extension staff did with collaborators from Virginia Tech and Texas A&M University to help private well owners impacted by Hurricanes Irma and Harvey last year. This work highlights just how important it is to be prepared for this year’s hurricane season and to make sure that if flooding does occur, those that depend on private wells for household use take the proper precautions to ensure the safety of their drinking water.
About 2.5 million Floridians (approximately 12% of the population) rely on private wells for home consumption. While public water systems are regulated by the U.S. Environmental Protection Agency to ensure safe drinking water, private wells are not regulated. Private well users are responsible for ensuring the safety of their own water.
Hurricanes Irma and Harvey
In response to widespread damage and flooding caused by Hurricane Harvey in Texas and Irma in Florida in August and September 2017, Virginia Polytechnic Institute and State University (VT) received a Rapid Research Response Grant from the National Science Foundation to offer free well water testing to homeowners impacted by flooding.
They partnered with Texas A&M AgriLife Extension’s Well Owner Network (run by Diane Boellstorff and Drew Gholson) and us, at UF/IFAS Extension to provide this service. The effort at VT was led by members of Marc Edward’s lab in the Civil Engineering Department: Kelsey Pieper, Kristine Mapili, William Rhoads, and Greg House.
VT made 1,200 sampling kits available in Texas and 500 in Florida, and offered free analysis for total coliform bacteria and E. coli as well as other parameters, including nitrate, lead, arsenic, iron, chloride, sodium, manganese, copper, fluoride, sulfate, and hardness (calcium and magnesium). Homeowners were also asked to complete a needs assessment questionnaire regarding their well system characteristics, knowledge of proper maintenance and testing, perceptions of the safety of their water and how to best engage them in future outreach and education efforts.
Response in the aftermath of Irma
Although the sampling kits were available, a major challenge in the wake of Irma was getting the word out as counties were just beginning to assess damage and many areas were without power. We coordinated the sampling effort out of Quincy, Florida, where I am based, and spread the word to extension agents in the rest of the state primarily through a group texting app, by telephone and by word of mouth. Extension agents in 6 affected counties (Lee, Pasco, Sarasota, Marion, Clay and Putnam) responded with a need for sample kits, and they in turn advertised sampling to their residents through press releases.
Residents picked up sampling kits and returned water samples and surveys on specified days and the samples were shipped overnight and analyzed at VT, in Blacksburg, VA. Anyone from nearby counties was welcome to submit samples as well. This effort complemented free well water sampling offered by multiple county health departments throughout the state.
In all, 179 water samples from Florida were analyzed at VT and results of the bacterial analysis are shown in the table below. Of 154 valid samples, 58 (38%) tested positive for total coliform bacteria, and 3 (2%) tested positive for E. coli. Results of the inorganic parameters and the needs assessment questionnaire are still being analyzed.
Table 1. Bacterial analysis of private wells in Florida after Hurricane Irma.
County
Number of samples (n)
Positive for total coliform (n)
Positive total coliform (%)
Positive for E. coli (n)
Positive for E. coli (%)
Citrus
1
0
0%
0
0%
Clay
13
5
38%
0
0%
Hernando
2
1
50%
0
0%
Hillsborough
1
1
100%
0
0%
Marion
19
5
26%
1
5%
Monroe
1
0
0%
0
0%
Pasco
40
19
48%
1
3%
Putnam
61
19
31%
0
0%
Sarasota
16
8
50%
1
6%
Overall
154
58
38%
3
2%
Of 630 samples analyzed in Texas over the course of 7 weeks post-Hurricane Harvey, 293 samples (47% of wells) tested positive for total coliform bacteria and 75 samples (2%) tested positive for E. coli.
What to do if pathogens are found
Following Florida Department of Health (FDOH) guidelines, we recommended well disinfection to residents whose samples tested positive for total coliform bacteria, or both total coliform and E. coli. This is generally done through shock chlorination by either hiring a well operator or by doing it yourself. The FDOH website provides information on potential contaminants, how to shock chlorinate a well and how to maintain your well to ensure the quality of your well water (http://www.floridahealth.gov/environmental-health/private-well-testing/index.html).
UF/IFAS extension agents that led the sampling efforts in their respective counties were: Roy Beckford – Lee County; Brad Burbaugh – Clay County; Whitney Elmore – Pasco County; Sharon Treen – Putnam and Flagler Counties; Abbey Tyrna – Sarasota County and Yilin Zhuang – Marion County.
We at IFAS Extension are working on using results from this sampling effort and the needs assessment questionnaire filled out by residents to develop the UF/IFAS Florida Well Owner Network. Our goal is to provide residents with educational materials and classes to address gaps in knowledge regarding well maintenance, the importance of testing and recommended treatments when pathogens and other contaminants are present.
Remember: Get your well water tested if flooding occurs
It’s important to remember that if any flooding occurs on your property that affects your well and/or septic system, you should have your well water tested in a certified laboratory for pathogens (total coliform bacteria and E. coli) and any other parameters your local health department may recommend.
Most county health departments accept samples for water testing. You can also submit samples to a certified commercial lab near you. Contact your county health department for information about what to have your water tested for and how to take and submit the sample.
You can search for laboratories near you certified by FDOH here: https://fldeploc.dep.state.fl.us/aams/loc_search.asp This includes county health department labs as well as commercial labs, university labs and others.
You should also have your well water tested at any time when:
The color, taste or odor of your well water changes or if you suspect that someone became sick after drinking your well water
A new well is drilled or if you have had maintenance done on your existing well
Testing well water once a year is good practice to ensure the safety of your household’s drinking water.
