Septic Systems A Complete Guide To Understanding How They Work and How To Keep Them Healthy
What Is A Septic System? Wastewater from a home, which includes the water from toilets, laundry, showers, sinks and dishwashers, does not always enter a sewer system to be treated and cleaned at a wastewater treatment plant. When sewer hookups are unavailable, the wastewater is treated by on-site wastewater treatment systems (septic systems). Types of Septic Systems Conventional Septic Systems Conventional septic systems include gravity distribution systems, which use gravity to drain wastewater from the house to the septic tank and the leach field (such as the system in the diagram below), and pressure systems, which utilize a pump to move wastewater to a secondary tank that then drains to the leach field. A conventional septic system.
Alternative Septic Systems Sometimes conventional septic systems may not be appropriate if there is a high water table, improper soil type or a lack of soil depth. In these cases, alternative septic systems are used in place of conventional septic systems. There are several types of alternative septic systems including mound systems, biofilters, sand filters, and constructed wetlands. Mound systems are pictured above and below. These systems are constructed using imported gravel and fill soil to create an elevated area where the partially treated wastewater from a septic tank can be released for further treatment within the mound. A mound septic system.
How Do Septic Systems Work? A typical septic system consists of four main components: the sewer pipe from the home, a septic tank, a leach field or seepage pit, and the soil. Components of A Septic System Sewer Pipe A buried pipe collects the wastewater from the home and directs it into the septic tank. Septic Tank The buried, watertight septic tank is typically made of concrete, fiberglass, or polyethylene. Wastewater is held long enough to allow solids to settle, forming a sludge layer on the tank s bottom. Oil and grease will float to the top, forming a scum layer. A conventional septic tank. The remainder of the wastewater, or effluent, forms a layer between the sludge and scum. Anaerobic bacteria, or bacteria that do not require oxygen, decompose the solid waste. The effluent leaves the septic tank through a pipe that leads to the leach field.
Leach Field The leach field is made up of leach lines installed in gravel-filled trenches or seepage pits. These trenches or pits must be at least five feet above seasonal high groundwater levels. Perforated pipes are also placed in the leach field trenches or pits in order for the effluent to be evenly distributed. Soil How surface water infiltrates to the groundwater zone. Microorganisms in the soil aid in removing harmful bacteria, nutrients, and viruses from the effluent. As water moves down through the soil, it is filtered and impurities are removed. The water will eventually reach a saturated zone, where soil pores are completely filled with water. This zone is commonly referred to as groundwater.
Keeping A Septic System Healthy Care & Maintenance Best Management Practices A properly functioning septic system not only helps reduce groundwater contamination, but it can save the homeowner money. To help maintain your septic system, follow these simple Best Management Practices (BMPs): Conserve water. Install low flow fixtures, such as sink aerators and low-water use toilets, and limit the amount of time spent in the shower. Fix all leaks. By conserving water, you can help keep your septic system from becoming overloaded. Put only domestic wastewater down the drains. Do not dump chemicals, such as Using less water keeps household cleaners and bleach, down septic tanks healthy! your drains as they can harm the good bacteria that are working in the septic tank. Do not dump oil and grease into the system. Do not put non-biodegradable items down the drains. Minimize the use of harsh chemicals.
Care & Maintenance Best Management Practices Limit the use of your garbage disposal. Do not flush pharmaceuticals and medicines down the toilet. They can kill the important bacteria that decompose the solid waste in the septic tank. Have the septic system pumped regularly. How often the septic system is pumped is determined by the tank size and number of people living in the Don t flush medicines home. Regular pumping helps remove down the drain! the accumulated sludge from the bottom of the septic tank and ensures that it will not enter and clog the leach field. Maintain the leach field. Do not plant vegetation with deep roots over the leach field as roots can cause costly and significant damage to pipes. Large trees such as eucalyptus, pine, and pepper should not be planted over or next to the leach field. Don t plant trees or Keep heavy equipment or objects off the leach field. deeply rooted plants Do not drive or build over the leach field. Do not allow above the leach field. heavy livestock animals to walk on the leach field. These activities can damage the leach field pipes. Divert surface flow away from the leach field. Too much water in the leach field will lead to oversaturation and the effluent will not infiltrate down into the soil properly. Don t let livestock walk above the leach field.
Septic Tank Pumping Frequency How often a septic tank should be pumped is determined by the tank size and number of people living in the home. The chart below can be used to determine how often a septic tank should be inspected and pumped. If guests, friends, or family frequently visit, the septic tank may need to be pumped more often. Recommended Septic Tank Pumping Frequency* Household Size - Number of Occupants 1 2 3 4 5 6 7 8 9 10 Septic Tank Size in gallons (Number of Bedrooms) Recommended Pumping Frequency (years) 1,000 gal (up to 3 bedrooms) 12.4 5.9 3.7 2.6 2.0 1.5 1.2 1.0 0.8 0.7 1,250 gal (up to 4 bedrooms) 15.6 7.5 4.8 3.4 2.6 2.0 1.7 1.4 1.2 1.0 1,500 gal (up to 6 bedrooms) 18.9 9.1 5.9 4.2 3.3 2.6 2.1 1.8 1.5 1.3 2,000 gal (up to 7 bedrooms) 25.4 12.4 8.0 5.9 4.5 3.7 3.1 2.6 2.2 2.0 *Adapted from Estimated Septic Tank Pumping Frequency, by Karen Mancl, 1984. Journal of Environmental Engineering. Volume 110.
Maintenance Log Keeping records of septic system inspections, pumping and other activities is vital for maintaining a healthy and properly functioning septic system. Use the Maintenance Log below to record important information and activities for your septic system. Important Information About Your Septic Tank Date Of Septic System Installation: Tank Size (Gallons): Date Septic Company & Phone Number Activity Completed Comments June 2016 US Septic 555-123-4567 Inspection Needs pumping next year
Spotting Potential Problems Causes of Septic System Failure Septic systems can fail, or stop functioning properly, for a variety of reasons. The two most common causes of septic system failures are broken pipelines in the leach field and blockages or clogging within the septic tank or leach field. The most common ways that pipes in the leach field get damaged are from tree roots invading the pipes or physical damage caused by vehicles, landscape installations or construction activity over the leach field. Tree roots that have Solids on the bottom of the septic tank can be completely blocked a septic disturbed and mix with the effluent when high volumes system pipe. of wastewater are introduced into the tank in a short period of time (such as in an evening when the washing machine, dishwasher, showers and toilets are all contributing to the amount of wastewater entering the septic tank). The effluent can then carry the solids into the leach field where clogging can occur. Solids can also enter the leach field if the septic tank is not pumped at the appropriate frequency as the sludge layer can build up in the tank until it overflows into the leach field.
Signs of Septic System Failure A strong, foul odor from sinks and drains or from around the septic tank or leach field. The odor is from the gases that are released during the decomposition of the solids in the septic tank. A properly functioning system will not release any unpleasant odors as the gases are supposed to be sealed within the tank. Slow draining pipes or wastewater that backs up into the home. When the septic tank and leach field are blocked or Vibrantly green vegetation over the leach not functioning properly, excess field during dry conditions. wastewater will make its way back into the house, usually in the lowest situated drain, sink or toilet. Patches of unusually vibrant vegetation above the leach field during dry conditions. When effluent in the leach field does not infiltrate into the ground properly, it can saturate the soil above the leach field. This influx of moisture will cause green lines or lush, thick vegetation compared to the plants in the surrounding areas. Pooling of effluent around the leach field or septic tank. Effluent should never be seen at the soil s surface. When any effluent (foul smelling liquid) is found on the ground s surface, the Effluent that is pooling above the septic system has failed. septic tank or leach field.
Correcting System Problems Septic System Failure Best Management Practices If you notice any signs of a failed septic system, immediately begin using the Best Management Practices (BMPs) listed below until you can get a licensed septic system contractor to the property. Conserve water until the repair is made. Do not cover up the exposed effluent with soil or other material as this may cause sewage to back up into the home. Rope or fence off the area where sewage is on the ground to keep people and animals from coming into contact with it. Do not pump or redirect exposed effluent to rivers, lakes, streams, or to abandoned wells or holes. This can lead to significant water quality impairment and it is illegal. Call a professional as soon as possible to help correct the problem.
Location and Records San Diego County DEH Contact Information Homeowners with properties located in San Diego County can obtain information regarding their septic system (including a septic system location map, the size of the septic tank, and date of the septic system installation) by contacting the San Diego County, Department of Environmental Health, Land and Water Quality Division, using the office contact information below or by going to the DEH website at: www.sdcounty.ca.gov/deh/. Central Kearny Mesa Office: County Operation Center 5500 Overland Ave., Suite 170 San Diego, CA 92123 (858) 565-5173 North County San Marcos Office: 151 East Carmel St. San Marcos, CA 92078 (760) 471-0730
What Is A Watershed? Watersheds A watershed is the area of land where all of the water that is under it (underground) and on the surface of it (such as stormwater runoff) drains to the same location, usually a lake or ocean. Everyone on Earth lives in a watershed! Most of the watersheds in San Diego County drain westward to the Pacific Ocean. An improperly designed, installed, or maintained septic system can contribute to the contamination of groundwater. This water can travel many miles within a watershed where harmful bacteria and nutrients can be a major threat to water resources. It is critical that all septic systems function properly or are repaired quickly.
Storm Drains & Runoff When it rains, surface water flows into creeks, rivers, and storm drains. Runoff from rain events, landscape irrigation, and agricultural irrigation is not treated to remove pollutants. Water that runs into storm drains goes directly to surface waters (such as creeks, rivers, lakes or an ocean), never entering municipal treatment facilities. In order to ensure that our groundwater, creeks, rivers, lakes, and oceans are healthy and safe for humans, plants and animals, only stormwater runoff should enter storm drains. Irrigation and agricultural runoff should not leave the property. Proper care and maintenance of septic systems will also ensure that the surrounding environment is not impacted by a failed septic system.
For more information and resources regarding septic systems and how to keep yours healthy and functioning, please visit www.missionrcd.org/learnaboutseptic/resources/. www.missionrcd.org (760) 728-1332 Funding for this project has been provided in full or in part through an agreement with the State Water Resources Control Board and the U.S. Environmental Protection Agency under the Federal Nonpoint Source Pollution Control Program (Clean Water Act Section 319). The contents of this document do not necessarily reflect the views and policies of the State Water Resources Control Board, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.