The subject of septic tanks has been a topic of recent conversation due to the intensity of the last red tide outbreak as well as the upcoming completion of the Phillippi Creek Septic System Replacement Program. It is widely known that septic tanks can contribute nitrogen pollution to local waterways like Phillippi Creek and Sarasota Bay. However, there can be some confusion as to what that means and how we can work with these systems to reduce the amount of unnecessary pollution.
If you don’t know whether you are on central sewer or septic, that would be the first place to start. Especially if you are renting, it’s important to know if you have septic and what maintenance you are responsible for. These systems don’t take care of themselves. You are the wastewater management department for your own tank.
What’s really happening down there?
After you flush your toilet, use your sink, or take a shower, all of that water flows out of your house into your septic tank.
- The solids settle out on the bottom.
- The scum layer, usually oils and grease, separates to the top
- The liquid part gets piped out of the tank to a drain field, usually in your yard
Overtime, you will need to pump out the bottom solid layer and the top scum layer, while the liquid layer will continue to be discharged to your yard.
The discharged liquid layer is distributed over the soil where microbes break down, transform, or remove bacteria, nitrogen, and other common pollutants found in wastewater. Therefore, the system relies heavily upon healthy soil microbes that need unsaturated, drier soil to work their magic.
Myth 1: A properly functioning septic tank does not contribute pollution to local waterways.
False! Even when working properly, conventional septic systems release nutrient pollution into soils. Septic tanks were originally designed around human health concerns. That means they are good at removing bacteria, but not nitrogen, pharmaceuticals, and other chemicals that may end up going down the drain.
As much as 60–70% of nitrogen pollution in raw wastewater typically exits the septic system into groundwater or local waterways. When these systems malfunction, even one household can become a large local source of nutrient pollution and bacteria.
Myth 2: The homes in Sarasota that are on septic are far enough from water bodies that any pollution is taken care of.
False! Many homes in the Phillippi Creek watershed are on septic. Although septic tanks can be quite appropriate for a the rural, land bound residence, many areas that currently have septic are way too close to Phillippi Creek and other nearby waterways. A general rule of thumb is that any residence within 900ft of a waterway (even if that waterway is a canal or ditch) should not be on septic.
Myth 3: As long as you’re inspecting/maintaining your tank every 3-5 years, there will be no problems.
False! Although the 3-5 year range is sufficient for most households, it really depends on how many people there are in your house (how much water you’re using) and how big your tank is. In the chart below, a four person household with a 500 gallon tank should be pumping out the tank every year.
How Can I Reduce Pollution From My Septic Tank?
Schedule regular inspection and pump outs.
Fix leaky fixtures and use less water during rainstorms to avoid overloading the system.
Compost kitchen scraps instead of using your garbage disposal.
Avoid driving or parking vehicles over your drain field to reduce compacting soils.
Don’t plant trees or shrubs over or near your drain field to prevent damage from roots.
Don’t dispose harmful chemicals down sinks and toilets that can kill the soil microbes in your system, including: poisons, gasoline, pesticides, paint, or medicines.
Don’t dump or flush items that can clog pipes, including:
- dental floss
- cotton swabs
- feminine hygiene products
- baby wipes (even “flushables”)
- cigarette butts
- coffee grounds
- cat litter
- paper towels
- fats, oils, or grease.