Household Wastewater: Why Should I be Concerned?

There are over 300,000 septic systems in Maine and many are sited very close to phosphorus sensitive lakes. Your septic system takes in wastewater from your home and discharges it back into the ground water system. Groundwater is intimately associated with surface water, our lakes, streams and ponds. In the humid East, 75% of surface water is supplied by groundwater recharge, so it is important that septic systems function effectively. The care you take maintaining your system and using it properly can reduce its effect on ground and surface water quality. For most people, treatment of wastewater is out-of-site and out-of mind until drains start backing up or other problems occur. Septic system failure is hazardous to health of humans and other living creatures as well as your lake. 

In many areas where people use septic systems, they also rely on drinking water from wells. A system that is improperly sited, improperly maintained, or overloaded, can discharge bacteria, viruses, nitrates, and hazardous chemicals to ground water — the same water you may use for drinking.

Even if your well or your neighbor’s well isn’t affected, the contaminants in the ground water may travel to nearby surface waters. A system that is failing, discharging wastewater to the surface, is the worst-case scenario for a lake.  In this case, phosphorus can flow unchecked into the lake and cause algae to grow. Systems that do not get pumped frequently, are overloaded, or undersized are the most likely to affect lake water quality.

How Does a Septic System Dispose of Wastewater?

What you put into your septic system through toilets, sinks, tubs and floor drains affects the quality of the wastewater and the ability of the system to handle it. Wastewater and the solids it carries travel into the septic tank.  Upon entering the tank the wastewater hits a baffle. The baffle stops the wastewater from rushing in and stirring up the sludge. Another baffle at the outlet keeps the scum layer, greases etc. that float on the surface, from leaving the tank. In the tank, most solids settle to the bottom, where bacteria partially break down the materials, forming sludge. Some material floats on the water, forming a layer of scum. The wastewater flows into the disposal field, carrying viruses, bacteria, nitrate and any chemicals added to the water. The most common disposal field design uses perforated pipe laid on a bed of screened or crushed stone. The size of the disposal field depends on the number of people using the system and on the permeability of the soil. Each perforated pipe, or distribution line, carries the wastewater into the field where the water moves through the stone and into the soil.

Soil and bacteria may not remove many of the toxic chemicals that come from putting cleaners, polishes, and detergents into the septic system. These chemicals contaminate the sludge in the septic tank, travel into ground water, and may kill the good bacteria that break down organic materials carried by wastewater.

Leach field and Soil

The soil acts as a filter by removing larger particles from the wastewater, and slows the rate of travel of the water. This allows time for bacteria and viruses to die off, and for good soil bacteria to break down some of the organic compounds. Soil type, distance to the shore and to ground water are important factors which determine the risk that your system places on water quality. Compared to porous sand, loam and clay soils have a greater long-term ability to hold nutrients, preventing them from moving through the soil. Clay soils can have an adverse effect on your system because they can clog the leach field. This causes nutrients and contaminants to bubble up to the surface and eventually end up in the lake. Sandy soils are troublesome because the septage wastes can leach very quickly into groundwater, drinking water, before good bacteria have a chance to break down the viruses, and other contaminants.

Shoreline properties often have septic systems that are close to the lake. During the spring or other times of high water the system can become flooded. Flooding can cause nutrients and contaminants to move much faster through the saturated soil and can reach surface water before being treated. 

Maintaining Your Septic System

The average life of a septic system is 15 to 25 years. How long yours will last depends on many factors including size, amount of use, how often you pump it, and what you put in the system. Here are some tips for better septic system performance

1. Use less water! Less water in the tank allows better settling of solids. The result is that fewer solids make it to the disposal field, so the leach lines are less likely to clog. A few ideas to decrease water use:

• Do only full dishwasher and laundry loads and take shorter showers.

• Use low-flow toilets, faucets and showerheads.

• Fix dripping faucets or leaky toilets immediately.

• Run water only when needed (to rinse when shaving or brushing teeth).

Spread out activities that use a lot of water over the day or week. For example, don’t run the dishwasher, do laundry and take showers all in a short period of time. Give the system a chance to work between large doses of water. This allows solids to settle in the septic tank and time for the bacteria in the tank and the soil to do their work.

2. Don’t put chemicals into your septic system. Household chemicals kill the good bacteria that help your septic system work and can contaminate the sludge, making sludge disposal more dangerous. Chemicals also travel through the disposal field and contaminate ground and surface water.
    

3. Don’t use the toilet as a wastebasket. Non-biodegradable materials such as diapers, sanitary napkins and cigarette butts will not break down in a septic tank. Flushing them down the toilet will cause the septic tank to fill faster and adds to litter problems when septage is spread. Avoid putting large amounts of fats and grease into your septic system.
    

4. Don’t use a garbage disposal. Finely ground solids can travel through the septic tank and clog the disposal field.
    

5. Have your septic tank pumped every three to five years. Timely pumping can extend the life of your system. Pumping a tank costs between $50 and $150. This is much cheaper than $3,000 to $5,000 for a new leach field. Some towns, neighborhoods or lake associations get together to arrange for a pumper to service an area at a reduced rate. This option may be available in your area.
    

6. Keep surface water away. Septic systems shouldn’t handle unnecessary water; divert roof drains and house footing drains and runoff from driveways and hillsides away from the septic system area.
    

7. Keep records of your system, including a pumping schedule, name of installer, age of system and a sketch of the location on your lot. This will help you maintain the system and boost the confidence of future buyers that the system is well cared for. (See the Septic System Record Sheet.)

How Do I Know if My Septic System Is Not Working?

Common signs that your septic system is not working include:

• Wet areas or areas of lush green growth in your lawn.

• Sewage odors.

• Slow draining of pipes or backup of wastewater into your home.

• Ponding or outbreak or wastewater onto the ground surface.

The cause of the problem could be clogged pipes between the house and the septic tank or a clogged distribution line or disposal field. If a heavy vehicle has driven over the field or a tree has fallen on it, the problem may be a broken or displaced distribution line. Also check the level of sludge in your septic tank, or have the level checked by a septic tank pumper or plumber. The tank could need pumping!

Solutions to Septic System Problems

• Consider drainage areas for the leach field as far away from the lake as possible for any new system you have installed.

• Design the system large enough to meet future demand.

• Before putting in a new septic system, consider banding together with your neighbors to create a community system.

• Plant vegetation between your drainage field and the lakeshore. Nutrients can be stopped and absorbed by the vegetated buffer before they reach the water. See the section of Lake*A*Syst entitled Landscape and Vegetated Buffers.

• Use other forms of waste disposal. There are non-leach field systems, which are perfect for property lots that are too close to the lake or too small to install a leach field. Composting and incinerator toilets are a good option. Holding tanks are also available, but they may need to be pumped out at the end of each season.

The solution depends on the cause: snakes may be used for some blockages of pipes; broken pipes must be replaced; or it may be necessary to pump the tank. If you see wet areas in your leach field and you haven’t had the septic tank pumped in a long time, simply pumping the tank may not be enough. Solids may have traveled out of the tank and clogged the disposal field. Finally, how old is your septic system? The life span of a typical disposal field is about 25 years. Eventually all septic systems will need to be replaced. 

Other Considerations

More and more seasonal camps along Maine’s lakes are being converted to year round homes. If you convert or expand your camp, improve the septic system at the same time. The increased demand and loading on the septic system may over work it, causing contaminants to enter the lake.

Septic System Worksheet

Take the Household Wastewater Self-Assessment.

Lake*A*Syst

• Camp Road Maintenance

• Landscape and Vegetated Buffers

• Lawn and Garden Care

• Recreation On and Around the Lake

• Agency Contact Information