Monday, April 15, 2013

The Basics of Living with a Well and Septic System

First, locate your well and septic system if you do not already know where they are (the as built diagram from the building department, or County Health District information can tell you this). Next you need to know the type of septic system you have: traditional or alternative. An alternative septic system is also known as an AOSS (alternative on-site sewage system). In Virginia AOSS are subject to regulations requiring annual inspections and maintenance.  Likewise you need to know the type of well, information on the construction of the well and the aquifer that supplies the well. Here in Prince William County information on all private wells drilled in the county after 1977 are in the files of the Prince William County Health District. The PW Health District has detailed files on over 20,000 wells. The “Water Well Completion Report” can tell you the age of the well, the depth of the well and casing, the approximate water zones and the yield at completion.  When a well is drilled or a home purchased the only water sampling that takes place is for a coliform bacteria test. There are many chemicals and naturally occurring contaminants that could make water unpalatable or unhealthy. In addition, a coliform test tells you almost nothing about the condition of the well.

A well should be a 6 inch diameter pipe with a bolted cap sticking a foot or more above the ground surface. What I have described is a modern drilled well. There are also dug and bored wells. Those types of wells fail sooner, are prone to go dry during droughts and because they are shallow (less than 40 feet deep) are more subject to pollution and surface contamination. If you have a dug or bored well, start saving money now to drill a new well (you will probably need it soon).  Drilled wells are more than 40 feet deep, typically more than 100. Virginia adopted statewide regulations on well construction in 1992 which conformed fairly closely to the PW County regulations. While many wells will last decades, it is reported that 20 years is the average age of well failure. Older well pumps are more likely to leak lubricating oil or fail. Well casings are subject to corrosion, pitting and perforation. Some kind of equipment failure usually occurs in the first 20 years.

Also, the well itself may fail after 20-30 years, though I personally know of a drilled well that lasted almost 50 years. You need to understand the characteristics  of the aquifer feeding your well to be aware of the factors that impact water quantity and quality. There are dry years and wet years and water availability will vary, though it is not always obvious. The groundwater aquifer tapped for water is not seen so you need to understand it to be aware of the water budget that you will have to live within before you run out of water. If a property has a low producing well, there are ways to deal with it. First is water conservation and the second is to increase water storage within the system. Water conservation involves changing water–use behavior such as taking shorter showers, but usually involves installing water saving devices like a front-loading washer (saves 20 gallons of water for each load),low flush toilets, flow restricting faucets and shower heads. Installing water saving appliances can reduce household water use by up to 30%. Water conservation is always a good idea when your water comes from a well, but increasing water storage can make a reliable 1 gallon a minute well viable for a modern household. However, it is possible that the production rate of the well itself has been falling and the well is failing. According to Marcus Haynes of the PW Health District the effective yield from a well can fall 40-50% or more over 20-30 years, so a low yielding well might have an effective life of only 25 years.

The well owner is responsible for ensuring that their water is safe to drink. Unlike public drinking water systems serving many people which have experts regularly checking the water quality, no one is looking out for families with their own wells. There are very few regulations nationally requiring the testing of private wells (New Jersey is a notable exception). In Virginia a well is only required to be tested for coliform bacteria at completion and mortgage lenders require the same test at purchase. However,at a minimum, all private water wells should be tested every year or so for total coliform bacteria, E Coli, nitrates, total dissolved solids and pH levels. Part of the price of your own water supply is maintaining it and testing it. You cannot taste bacterial contamination from human and animal waste and you cannot taste nitrate/ nitrite contamination. Total coliform counts give a general indication of the sanitary condition of a water supply and nothing more. Total coliform includes bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste. Fecal coliform is the group of the total coliform that is considered to be present specifically in the gut and feces of warm-blooded animals. E. coli is the best indicator of fecal pollution and the possible presence of pathogens. If a sample is positive for coliform bacteria a second test for fecal coliform and E Coli is usually performed. Anything that you pour down the drain, flush down the toilet, pour into your yard or spray around your house could end up contaminating the groundwater at your own home or your neighbors’ homes, and you might want to consider testing for these if you are aware of a history of use.

A septic system has no ability to treat solvents, oils, grease, household chemicals and pesticides. These substances may damage your septic system, cause the system to back-up into your basement, untreated sewage to surface in your yard, and/or contaminate the groundwater. A typical septic system has four main components: a pipe from the home, a septic tank, a leach field (alternative systems might have drip fields, sand mounds or peat tanks where a leach field is not possible or has failed), and the soil. The system is designed to remove most of the biological contamination by settling and bacterial digestion so that the soil is not overwhelmed and can “polish” the water before it is returned through the soil to the groundwater. Never dispose of anything but human biological waste (and a reasonable amount of toilet paper) in your septic system. Limit the use of household chemical cleaners, solvents, bleach, pesticides and termite treatments sprayed into the ground.  

The septic tank is a buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum). It also allows partial decomposition of the solid fecal materials. Anaerobic (without oxygen) digestion takes place with the aid of bacteria that came from human digestive tracks and most of the fecal solids are converted to carbon dioxide, water and other byproducts. The process is not completely efficient and fecal solids and other materials that find their way into the septic tank will accumulate over time. To keep a septic system operating optimally, a septic tank must be pumped every few years to remove the scum and solid layers. Steady use of water throughout the day and water conservation should be practiced because too large a flow of waste water and the solids in the tank will be stirred up and be carried out to the drain field.

Also, the drain field does not have an unlimited capacity. The more water your family uses, the greater the likelihood of problems with the septic system, so it is important to fix all leaks, and stop toilets from running and practice water conservation.  In the Chesapeake Bay watershed many homes are within areas designated  resource protected areas that requires a septic tank pumpout at least every five years, but that may not be frequent enough depending primarily on the size of your tank, the number of people in the household contributing to the volume of your wastewater, the volume of solids in your wastewater and whether you use a garbage disposal or have a water treatment system. Excess water flow through the septic system can cause the solid sludge buildup and floating scum (grease, oil, dead skin cells, etc.) to flow out of the tank and travel into the leach field area. Some newer systems have screens and filters to keep solids from entering the leach field. These filters and screens become clogged and need to be cleaned out regularly or the system will back up into the house.

Finally, you need to limit what goes down the drain to prevent bacterial die-off in the tank so that it will continue to function as designed. Die-off of the bacteria necessary for a septic system to perform properly has been seen in experiments where excessive amount of harsh household chemicals were added to the septic tank. As little as of 1.85 gallons of liquid bleach, 5.0 gallons of liquid Lysol cleaner, or 11.3 grams of Drano drain cleaner added to a 1,000-gallon septic tank have caused die-off of the bacteria in experiments. Other factors that can cause die-off include the excessive use of anti-bacterial agents, and, in certain cases, antibiotic medications taken by members of a household. However, in normal use, you do not need to add a chemical or biological stimulator or an enhancer to a septic tank that is designed, operated, and maintained properly. The naturally occurring bacteria are already present within human fecal matter are adequate for the system to function properly. Contrary to popular belief, chemical additives, such as caustic hydroxides and sulfuric acid, should never be added to a septic system. Adding these chemicals will destroy the bacterial population in the septic tank, change the permeability characteristics of the soil absorption system, and may cause groundwater contamination.

Septic drainfields and alternative secondary treatments like peat tanks and sand mounds also have a limited life. The life of a septic drainfield is dependent on how the system is managed, the frequency of septic tank pump outs, and the number of people living in a house, but 20-30 years may be the life of those systems- even when well managed.

The following actions to protect groundwater from contamination and are based on recommendations from the National Groundwater Association:
1. Properly store hazardous household substances like paints, paint thinners, petroleum products, fertilizers, herbicides, insecticides, and cleaning products in secure containers. Try to minimize the use of these substances in your home and yard.
2. Mix hazardous household substances over concrete or asphalt where they can be cleaned up or absorbed onto disposable media like paper towels and then properly disposed of with hazardous material waste.
3. Dispose of hazardous household wastes at an appropriate waste disposal facility or drop-off. Most landfills and city trash programs have these drop-offs.
4. Do not put hazardous household wastes down the drain or in the toilet EVER. Do not wash paint brushes or containers in the sink. Minimize the use of bleach, chemical disinfectants and antibacterial agents.
5. Do not put any wastes down a dry or abandoned well or use sinkholes as waste disposal holes.
6. Service your septic system regularly. At a minimum pump your septic tank every 3-5 years.
7. Check your private drinking water well annually to make sure the sanitary seals are intact.
8. Decommission abandoned wells on your property using a qualified water well contractor

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