Many of Florida’s historic first magnitude springs are classified as nitrogen impaired. Image credit: UF/IFAS Communications
Septic systems are an effective means of treating wastewater when they are properly designed, constructed and maintained. Conventional systems are designed from a public health perspective and have been widely used since the 1940s to remove pathogens and protect human health. About 30% of Florida’s population relies on septic systems, which treat and dispose household wastewater drained from bathrooms, kitchens and laundry machines.
However, septic systems were not designed to remove nutrients. A conventional system removes only about 30 percent of the nitrogen that flows into it. Even a well-maintained system will become a source of nitrogen (particularly nitrate-nitrogen) to the surrounding soil in the drainfield, and may leach to groundwater. Excess nitrogen in Florida’s waterbodies can be a contributing factor to ecological community degradation and increases in algae.
What alternatives are there to conventional septic systems?
Many enhanced nitrogen removal technologies exist, but only those approved by the Florida Department of Health (FDOH) can be installed. Conventional septic systems are made up of a septic tank and a drainfield (or leachfield). Advanced treatment systems add steps to conventional system processes to improve contaminant removal. Types of advanced nitrogen removal technologies available include:
- Aerobic Treatment Units ATUs are made of fiberglass, polyurethane or concrete. Unlike conventional systems, ATUs introduce air into the sewage in the tank using a pump. By aerating waste, the organic matter in the tank is broken down faster than in a conventional system. Effluent from an ATU is discharged into a drainfield for further treatment in the soil, just as with a conventional septic system. ATUs require higher energy input than conventional septic systems to power the aerator, and regular operation and maintenance to sustain performance ATU example from the US EPA
- Performance Based Treatment Systems PBTS are specialized systems designed by professional engineers to meet specific levels of contaminant removal based on site and/or situation requirements. There are many proprietary commercial options available. Designs often include an ATU. Like ATUs, PBTS require higher energy input than conventional septic systems to power pumps, and regular maintenance is needed to sustain performance.
- In-Ground Nitrogen Removing Biofilters INRB are also referred to as modified drainfields. These systems are passive, which means they require no electric aerators or pumps to treat wastewater, and maintenance requirements are lower than those for ATUs and PBTS. INRBs are nitrogen-reducing media layers placed underneath a conventional drainfield.
Ammonium-nitrogen in wastewater leaving the septic tank moves down through the Drainfield Area soil and an additional oxygen-rich zone (Unsaturated Nitrification Soil) to promote conversion into nitrate-nitrogen. Wastewater then passes through a low-oxygen, carbon-rich zone to promote denitrification (Woodchips/Soil Mix Denitrification Media). Denitrification is a process by which specialized bacteria convert nitrate into nitrogen gas that escapes into the atmosphere. This reduces the amount of nitrogen that can leach into groundwater.
FDOH provides comprehensive information about advanced treatment systems and requirements on their product listing and approval requirement web page.
Where are advanced treatment systems required?
The short answer is wherever a septic system remediation plan to protect Florida Springs has been put into place. The 2016 Florida Springs and Aquifer Protection Act was passed to protect 30 ‘Outstanding Florida Springs.’ The majority are historic first magnitude springs, springs with flows of more than 100 cubic ft/second. Twenty-four of these springs are identified as nitrogen impaired by the Florida Department of Environmental Protection.
If septic systems contribute more than 20% of the nitrogen load to the impaired spring, a remediation plan takes effect in specific areas (Priority Focus Areas) that are particularly susceptible to nitrogen pollution. Septic system remediation plans require new development to connect to central sewer where available. If this isn’t an option, new construction on lots of less than 1 acre must include advanced nitrogen-removal technology. In the Panhandle, areas around Wakulla Springs and Jackson Blue Springs have remediation plans.
The best source of information about specific remediation plans and whether or not you live in a Priority Focus Area is FDOH. Contact your local County Department of Health Office to find out if you live in a PFA or if you have questions about septic tank requirements, permitting and approved advanced nitrogen-treatment features for septic systems.
For more information and resources about conventional septic systems and advanced treatment system visit our UF/IFAS Septic Systems website.
Senate Bill 712 ‘The Clean Waterways Act’ was signed into Florida law on June 30, 2020. The purpose of the bill is to better protect Florida’s water resources and focuses on minimizing the impact of known sources of nutrient pollution. These sources include septic systems, wastewater treatment plants, stormwater runoff as well as fertilizer used in agricultural production.
Senate Bill 712 focuses on protecting Florida’s water resources such as Jackson Blue Springs/Merritt’s Mill Pond, pictured here. Credit: Doug Mayo, UF/IFAS.
What major provisions are included in SB 712?
Primary actions required by SB712 were listed in a news release by Governor Desantis’ staff in June 2020 as:
- Regulation of septic systems as a source of nutrients and transfer of oversight from the Florida Department of Health (DOH) to the Florida Department of Environmental Protection (DEP).
- Contingency plans for power outages to minimize discharges of untreated wastewater for all sewage disposal facilities.
- Provision of financial records from all sanitary sewage disposal facilities so that DEP can ensure funds are being allocated to infrastructure upgrades, repairs, and maintenance that prevent systems from falling into states of disrepair.
- Detailed documentation of fertilizer use by agricultural operations to ensure compliance with Best Management Practices (BMPs) and aid in evaluation of their effectiveness.
- Updated stormwater rules and design criteria to improve the performance of stormwater systems statewide to specifically address nutrients.
How does the bill impact septic system regulation?
The transfer of the Onsite Sewage Program (OSP) (commonly known as the septic system program) from DOH to DEP becomes effective on July 1, 2021. So far, DOH and DEP submitted a report to the Governor and Legislature at the end of 2020 with recommendations on how this transfer should take place. They recommend that county DOH employees working in the OSP continue implementing the program as DOH-employees, but that the onsite sewage program office in the State Health Office transfer to DEP and continue working from there. DOH created an OSP Transfer web page where updates and documents related to the transfer are posted.
How does the bill impact agricultural operations?
SB 712 affects all landowners and producers enrolled in the Florida Department of Agriculture and Consumer Services (FDACS) BMP Program. Under this bill:
- Every two years FDACS will make an onsite implementation verification (IV) visit to land enrolled in the BMP program to ensure that BMPs are properly implemented. These visits will be coordinated between the producer and field staff from FDACS Office of Agriculture and Water Policy (OAWP).
- During these visits (and as they have done in the past), field staff will review records that producers are required to keep under the BMP program.
- Field staff will also collect information on nitrogen and phosphorus application. FDACS has created a specific form, the Nutrient Application Record Keeping Form or NARF where producers will record quantities of N and P applied. FDACS field staff will retain a copy of the NARF during the IV visit.
FDACS-OAWP prepared a thorough document with responses to SB 712 Frequently Asked Questions (FAQ’s). It includes responses to questions about site visits, the NARF and record keeping, why FDACS is collecting nutrient records and what will be done with this information. The fertilizer records collected are not public information, and are protected under the public records exemption (Section 403.067 Florida Statutes). For areas that fall under a Basin Management Action Plan (like the Jackson Blue and Wakulla Springs Basins in the Florida Panhandle), FDACS will combine the nitrogen and phosphorus application data from all enrolled properties (total pounds of N and P applied within the BMAP). It will then send the aggregated nutrient application information to FDEP.
Details of how all aspects of SB 712 will be implemented are still being worked out and we should continue to hear more in the coming months.
Special care needs to be taken with your septic system after flooding. Image: B. White NASA. Public Domain
During and after floods or heavy rains, the soil in your septic system drainfield can become waterlogged. For your septic system to treat wastewater, water needs to drain freely in the drainfield. Special care needs to be taken with your septic system under flood conditions.
A conventional septic system is made up of a septic tank (a watertight container buried in the gound) and a drainfield. Image: Soil and Water Science Lab UF/IFAS GREC.
A conventional septic system is made up of a septic tank and a drainfield or leach field. Wastewater flows from the septic tank into the drainfield, which is typically made up of a distribution box (to ensure the wastewater is distributed evenly) and a series of trenches or a single bed with perforated PVC pipes. Wastewater seeps from these pipes into the surrounding soil. Most wastewater treatment occurs in the drainfield soil. When working properly, many contaminants, like harmful bacteria, are removed through die-off, filtering and interaction with soil surfaces.
What should you do if flooding occurs?
The U.S. Environmental Protection Agency (EPA) offers these guidelines:
- Relieve pressure on the septic system by using it less or not at all until floodwaters recede and the soil has drained. Under flooded conditions, wastewater can’t drain in the drainfield and can back up in your septic system and household drains. Clean up floodwater in the house without dumping it into the sinks or toilet. This adds additional water that an already saturated drainfield won’t be able to process. Remember that in most homes all water sent down the pipes goes into the septic system.
- Avoid digging around the septic tank and drainfield while the soil is waterlogged. Don’t drive vehicles or equipment over the drainfield. Saturated soil is very susceptible to compaction. By working on your septic system while the soil is still wet, you can compact the soil in your drainfield, and water won’t be able to drain properly. This reduces the drainfield’s ability to treat wastewater and leads to system failure.
- Don’t open or pump the septic tank if the soil is waterlogged. Silt and mud can get into the tank if it is opened and can end up in the drainfield, reducing its drainage capability. Pumping under these conditions can cause a tank to float or ‘pop out’ of the ground, and can damage inlet and outlet pipes.
- If you suspect your system has been damaged, have the tank inspected and serviced by a professional. How can you tell if your system is damaged? Signs include: settling, wastewater backs up into household drains, the soil in the drainfield remains soggy and never fully drains, a foul odor persists around the tank and drainfield.
- Keep rainwater drainage systems away from the septic drainfield. As a preventive measure, make sure that water from roof gutters doesn’t drain towards or into your septic drainfield. This adds an additional source of water that the drainfield has to process.
- Have your private well water tested if your septic system or well were flooded or damaged in any way. Your well water may not be safe to drink or use for household purposes (making ice, cooking, brushing teeth or bathing). You need to have it tested by the Health Department or other certified laboratory for total coliform bacteria and coli to ensure it is safe to use.
For more information on septic system maintenance after flooding, go to:
More information on having your well water tested can be found at:
More Information on conventional and advanced treatment septic systems can be found on the UF/IFAS Septic System website
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.
Contact information for Florida Health Departments can be found here: County Health Departments – Location Finder
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:
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.
Pitt Spring in the Florida Panhandle is one of more than 1,000 freshwater springs in the state. Springs serve as ‘windows’ to groundwater quality, since the water that flows from them comes largely from the Upper Floridan Aquifer. Photo: A. Albertin
As Florida residents, we are so fortunate to have the Floridan Aquifer lying below us, one of the most productive aquifer systems in the world. The aquifer underlies an area of about 100,000 square miles that includes all of Florida and extends into parts of Alabama, Georgia and South Carolina, as well as parts of the Atlantic Ocean and the Gulf of Mexico (Figure 1). The Floridan Aquifer consists of the Upper and Lower Floridan Aquifer.
Figure 1. Map of the extent of the Floridan Aquifer. Areas in gray show where the aquifer is buried deep below the land surface, while areas in light brown indicate where the aquifer is at land surface. Many springs in Florida are found in these light brown areas. Source: USGS Publication HA 730-G.
Aquifers are immense underground zones of permeable rocks, rock fractures and unconsolidated (or loose) material, like sand, silt and clay that hold water and allow water to move through them. Both fresh and saltwater fill the pores, fissures and conduits of the Floridan Aquifer. Saltwater, which is more dense than freshwater, is found in all areas of the deeper aquifer below the freshwater.
The thickness of the Floridan Aquifer varies widely. It ranges from 250 ft. thick in parts of Georgia, to about 3,000 ft. thick in South Florida. Water from the Upper Floridan Aquifer is potable in most parts of the state and is a major source of groundwater for more than 11 million residents. However, in areas such as the far western panhandle and South Florida, where the Floridan Aquifer is very deep, the water is too salty to be potable. Instead, water from aquifers that lie above the Floridan is used for water supply.
There are actually several major aquifer systems in Florida that lie on top of the Floridan Aquifer and are important sources of groundwater to local areas (Figure 2):
- The Sand and Gravel Aquifer in the far western panhandle is the main source of water for Santa Rosa and Escambia Counties. It is made up of of sand and gravel interbedded with layers of silt and clay.
- The Biscayne Aquifer supplies water to Dade and Broward Counties and southern Palm Beach County. A pipeline also transports water from this aquifer to the Florida Keys. The aquifer is made of permeable limestone and less permeable sand and sandstone.
- The Surficial Aquifer System (marked in green in the map in Figure 2) is the major source of drinking water in St. Johns, Flagler and Indian River counties, as well as Titusville and Palm Bay. It is typically shallow (less than 50 ft. thick) and is often referred to as a ‘water table’ aquifer, but in Indian River and St. Lucie Counties, it can be up to 400 ft. thick.
- Not included in Figure 2 is a fourth aquifer, the Intermediate Aquifer System in southwest Florida. It lies at a depth between the Surficial Aquifer System and the Floridan Aquifer. It is found south and east of Tampa, in Hillsborough and Polk counties and extends south through Collier County. It is the main source of water supply for Sarasota, Charlotte and Lee counties, where the underlying Floridan Aquifer is too salty to be potable.
Figure 2. A map of four major aquifer systems in the state of Florida at land surface. The Floridan Aquifer (in blue) underlies the entire state, but in areas north and east of Tampa it is found at the surface. The Surficial (green), Sand and Gravel (red), and Biscayne Aquifer (purple/pink) lie on top of the Floridan Aquifer. A confining unit (area in brown) consists of impermeable materials like thick layers of fine clay that prevent water from easily moving through it. Source: FDEP.
All of the aquifer systems in Florida are recharged by rainfall. In general, freshwater from deeper portions of the aquifer tends to have better water quality than surficial systems, since it is less susceptible to pollution from land surfaces. But, in areas where groundwater is excessively pumped or wells are drilled too deeply, saltwater intrusion occurs. This is where the underlying, denser saltwater replaces the pumped freshwater. Florida’s highly populated coastal areas are particularly susceptible to saltwater intrusion, and this is one of the main reasons that water conservation is a major priority in Florida.
More information about the Floridan Aquifer System and overlying aquifers can be found at the Florida Department of Environmental Protection (https://fldep.dep.state.fl.us/swapp/Aquifer.asp#P4) and in the UF EDIS Publication ‘Florida’s Water Reosurces’ by T. Borisova and T. Wade (https://edis.ifas.ufl.edu/fe757).