10 Rules for Buying a Home with a Well and Septic System

Well and septic systems are simply mechanical components to a house. What makes them different is that they are specifically excluded from home inspections, are very expensive to replace and essential. There are times and instances that a well or septic system has no good replacement location and then the home owner has a large problem on their hands that will cost tens of thousands of dollars to solve. Make sure that you do not buy someone else’s problem and make it your own.  When shopping for a home, there are some “fatal flaws” that can quickly and easily be identified. This is the list of quick observations and the reasons they might be a problem for a well and septic system to quickly eliminate properties as potential big problems, require further investigation or to factor the price of repair or replacement into an offer on a house. (For updated articles on this topic see "The House has a Well...") 

1.      The house must have 2-3 acres of land.

2.      Do not buy a home with a dug or bored well.

3.      The visible well should be a 6 inch diameter pipe with a bolted cap sticking a foot out of the ground.

4.      Water from the road, driveway, and downspouts should not drain to the well.

5.      Rainwater should flow away from not to the wellhead.

6.      If the well was drilled before 1992 don’t buy the house.

7.      The well head must be at least 100 feet from the nearest edge of the septic drainfield and any backyard chicken or poultry yards and coops. 

8.      The well head must be at least 50 feet from the nearest corner of the house.

9.      Ask to see the maintenance records for the septic system and well along with water test results (having records is an indication of proper maintenance).

10.   When you make an offer on a house a satisfactory water test and a professional septic inspection should be included in your contingencies.

This is what a drilled well looks like

The well and septic system should be easily identified and pointed out. 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 drilled well there are also dug and bored wells. Do not buy a home with a dug or bored well. 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. Drilled wells are more than 40 feet deep, typically more than 100. In Virginia well drillers are required to file a drilling log with thecounty and comply with drilling regulations since 1992. If the well was drilled before 1992 don’t buy the house unless you have factored well component replacement into the price and you should be thinking about the costs and possibilities of well replacement.  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. Septic drainfields 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, too.

If a property has a well and septic system and has less than 2-3 acres, do not buy it. This is simple there will not be enough room for a replacement well and septic system when the time comes (all systems fail eventually) and the well is likely to be too close to the home’s own or the neighbor’s septic system. The most common contamination problem for a well is an adjacent septic system and research done in Duchess county New York identified density of septic systems as an easy indicator of nitrate contamination to groundwater. The Dutchess County study and another study performed in North Carolina found that overall average density of on-site waste disposal (traditional septic or alternative) should not exceed one unit per 2-3 acres for an average size house to ensure water quality and recharge in groundwater supplies. The controlling factor in minimum lot size requirements in the northeast appears to be maintaining water quality, not groundwater recharge. Adequate dilution, soil filtration and time are necessary to ensure sustainable water quality. It is often surprising how close to a private well the recharge zone is.

Failed drainfield. Picture from NC Health Department

 So, while you are walking around outside make sure that the well head is at least 100 feet from the nearest edge of the septic drainfield and 50 feet from the nearest corner of the house. It can often be difficult to identify a septic drainfield while walking in the yard. Newer systems often have plastic caps to the distribution valve, but older systems often do not- the distribution valve is buried. In Virginia (and most places) if a well is more than 100 feet deep the septic leach field need be only 50 feet away, but there are many wells like mine that have more than one water level and the shallower one is less than 100 feet deep (in my case 46 feet) making the well much more susceptible to contamination for the septic effluent leaching into the ground. If the well is too close to the drainfield, move on to the next house in your search, the well could too easily be impacted by the septic drainfield.

The final treatment for all septic systems is septic system effluent (after any intermediate treatment steps in an alternative system) is filtering of the wastewater through the soil. The method of sewage treatment with a septic system is soil organisms and soil filtration and adsorption. Whatever was flushed down the toilet or poured down the drain over the years has found its way into the drainfield and potentially to the groundwater. Not only should the well head be at least 100 feet from the nearest edge of the drainfield, the drainfield should be downhill and down gradient for the well. The land that my house sits on has a predominately southeast slope to the river at the bottom of the property. It is a fairly safe bet that the groundwater flows with the land topography towards the river.  

Two septic tank lids and filter for alternative septic system. 

Look for the septic tank. The tank should not be entirely buried and at least one port should be visible in the yard. If the tank is entirely buried- move on, do not buy the house because it is a safe bet that the tank has never been pumped and the entire septic system will have to be replaced.  The solids, scum and grease that accumulate in the septic tank need to be pumped out and disposed of every few years. If not removed, these solids will eventually overflow the septic tank, accumulate in the drain field, and clog the pores in the soil and the openings in the pipes. While some clogging of soil pores occurs slowly even in a properly functioning system, excess solids from a poorly maintained tank or a tank where enzyme additives were used instead of pumping the tank can completely close all soil pores so that no wastewater can flow into the soil. The sewage effluent will then either back up into the house, flow across the ground surface over the drain field, or find another area of release in the septic system. In some cases where the drain field has become clogged and no longer can adequately absorb the wastewater, the toilets and sinks might not drain freely. A black residue may remain at the bottom of the toilet.  If the drain field can absorb the effluent, but no longer treat it, the sewage may contaminate the groundwater or surface water with fecal coliform bacteria. On a dry day if there is a soggy area of the yard the drainfield may already be failing.

The reason a well should be more than 50 feet from a house is that in Virginia (and many other locations) building codes require that a construction site be pretreated for termites, and many homeowners spray gallons of pesticides into the ground to treat or prevent termites.  (There are other approaches to termite management, but most homeowners do not use them. Termite bates are easy to spot in the yard and indicate that chemical barriers are not used. ) http://greenrisks.blogspot.com/2011/10/low-impact-termite-management.html The most popular professionally applied conventional chemical treatments on the market are Premise (imidacloprid), Termidor (finpronil), and Phantom (chlorfenzpyr). These chemicals range from slightly toxic to very toxic and vary in their solubility and affinity for soil. They are less environmentally persistent and more rapidly biodegradable, than previous generations of chemicals. This all means that they breakdown faster and do not last as long, but also may allow their breakdown products to migrate to the shallow groundwater.

Sentricon termite bate station

Other posts:
https://greenrisks.blogspot.com/2019/06/what-to-know-when-buying-home-with-well.html
https://greenrisks.blogspot.com/2020/03/what-to-know-if-buying-house-with-well.html