Prince William Health District Offers Essential Services to Well Owners

Last week I went down to Woodbridge to meet with Marcus Haynes, who is an Environmental Health Specialist with the Prince William Health District and the “water and well guy” for the county.  The Prince William Health District is a branch office of the Virginia Department of Health that administers the health related laws throughout the state. Marcus is part of a six person team located in Building 5 at the Prince William County Complex in Woodbridge that administers the health laws and regulations relating to private water supplies and sewage systems, water well construction regulations, and septic and alternative on-site sewage system construction and operation regulations. In addition, the PW Health District provides help and guidance for private well and traditional and alternative septic systems.

Marcus has been with the PW Health District since 1977, starting on the job the day Prince William County first implemented county wide well construction regulations. Those regulations were very progressive for their time and quite similar to the current sate wide regulation implemented in 1992 and still in effect today. Through experience, additional training and certification, Marcuse has an almost encyclopedic knowledge about the groundwater in our county and water wells in general. He knows the fracture density and thus groundwater availability in all of the county and thus knows where well yields are a problem. In years past he worked in conjunction with the US Geological Survey to develop their study of the extent of chlorinated solvent contamination in the Culpeper groundwater basin in Prince William County from the historic operations of IBM Corp.  

  

From 1970 to 1975, IBM used chlorinated solvents to degrease electrical components at its plant in Manassas, Virginia. Spills and poor disposal and containment practices contaminated the groundwater. The PW Health District was instrumental in identifying that the contamination had reached the (now abandoned) public supply wells and private wells serving about 32,000 people. Ultimately, IBM's funded the study of the groundwater (1), installed monitoring wells and under RCRA (federal Resource Conservation and Recovery Act) removed the contaminated soil and contained and/ or eliminated the contaminated groundwater. IBM connected homes with contaminated wells to Prince William County's water supply system which obtained other sources for water supply. It is hoped that these days pollution problems of this magnitude will be prevented by the modern web of environmental and health regulations, but it was with the help of the PW Health District that the problem was identified.

The mission of the PW Health District has remained consistent over the years; to protect the Public Health and the water resources of the Commonwealth. However the understanding of the interconnection of surface water, groundwater, and the increase in population and the density within the county of on-site private water and sewage treatment systems has changed the emphasis and nature of their work. There was a time when the homeowner was more directly involved in the construction of their water wells and septic/ on-site sewage systems and Marcus and the Environmental Health team did all certifications and dealt with the homeowner directly. These days many of these steps have been outsourced to the private sector while staff addresses problems, VPDES permit system and critical issues. Though each well requires a permit, the homeowner can have the well driller act as their agent and site visit, inspections and sampling can also be performed by the private sector. In subdivisions like mine, the well and water systems were built by four different subcontractors and the coordination depended on the interest, knowledge and skill of the project foreman. The homeowner is removed from the process until there is a problem and then lacking any background or knowledge the homeowner does not know where to turn. If you have a problem with a private water or waste system, call the PW Health District. If you have a concerns or want background information you might call me at the Virginia Master Well Owners Network for information.

Marcus would like to see the homeowner’s relationship with the PW Health District begin before the even purchasing a home. Information on all private wells drilled in the county after 1977 are in their files. The PW Health District has detailed files on over 20,000 wells. Before buying a home with a well you should have the well drillers log in hand. 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. These are the most basic facts needed to evaluate a well and water system.   The best place for all homeowners with private drinking wells to start is to call or email the PW Health District and request a copy of the “Water Well Completion Report” and ask if there is other information in the file. You should also take a look at the brochure “TenTips for Managing Your Private Well Water Supply.” Prince William Office of Internet Technology is working to computerize the Environmental Health Records in the GIS system, but for now you will have to call and ask them to email (or fax) you the information. Marcus’ phone number is (703) 792-6343 and his email is Marcus.Haynes@vdh.virginia.gov. (He is pretty responsive to routine requests, but water well problems move to the top of the pack and get fast turnaround. I have waited on hold while he has scanned and emailed me a copy of the “Water Well Completion Report” for a VAMWON client in stationed in Afghanistan with a water well in the county that had stopped working.)

When a well is drilled 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. Before buying a home you need to perform a more extensive testing of the water. For this you can sample and test using a private certified laboratory or you can have the Health District sample your water for you. The Health District charges $80-85 for the first chemical or contaminant and $20 for each additional contaminant. The Virginia Household Water Quality Program recommends that water be analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria (if coliform is present) and any industrial or agricultural chemicals that may be of concern at the particular location. That can add up to quite a bill, but a home is probably the most expensive purchase you will ever make- verify the quality of the water.

Marcus also recommends that before buying a home with a private well you verify the capacity and the condition of the well. His rule of thumb is 5 gallons/minute is a safe yield to supply on-demand water for a typical household, but homes can have much lower yielding wells and still provide adequate water at least sometimes. Be aware that over time the yield of a well falls and what was an adequate well 20 years ago may not be now. Groundwater enters a well through fractures in the bedrock and overtime debris, particles, and minerals clog up the fractures and the well production falls. Marcus said that the drop in water recharge rate could be 40-50% or more over 20-30 years. A low yielding well might have a functional life of only 25 years. So, if you are buying a home with an older well having a well driller perform an accurate assessment of the well’s capacity would be important. A well recharge can be estimated by running water from the pump and measuring the top of the water level in the well. If it does not change, then the well recharges faster than the pump rate. If the level is falling then the each foot in a typical 6 inch cased well represents about 1.5 gallons.  A more accurate rate to determine the recharge rate is to use a compressor to blow all the water (and deposits at the bottom of the well) out of the well and time how long it takes the well column to recharge. The well driller can also examine the condition of the casing, wiring, pump and the well components in the house. 

A private well owner is responsible for their water supply. The PW Health District is a treasure, providing incredible expertise and valuable services for well and septic system owners throughout the county. 

(1)    Nelms, D.L., and Richardson, D.L., 1990, Geohydrology and the occurrence of volatile-organic compounds in ground water, Culpeper basin of Prince William County, Virginia: U.S. Geological Survey Water-Resources Investigations Report. This report funded by IBM is still a fabulous resource to understanding the groundwater in Prince William County. 

Using Your Water Well as a Standing Column Well for Geothermal

Adopted from Orio 1999

Through the Virginia Department of Health I received a contact from a homeowner interested in installing a ground source heat pump utilizing his current drinking water well as both a water supply well and a standing column thermal exchange well for the geothermal heat pump. He apparently had run across this idea in some materials by Carl Orio. In truth, Mr. Orio is the man.  Mr. Orio has been working with geothermal heat pumps since 1974 when he founded WESCORP. Since that time he has expanded his knowledge and experience about geothermal heat pumps leading the way and is the co-author of practically everything including the New York City "Geothermal Heat Pump Manual" and ASHRAE funded research papers.

Though standing column wells have been around since the advent of geothermal heat pump systems, only  recently are they receiving  more attention because of their superior performance in regions with suitable hydrological and geological conditions (Orio 1994, 1995, 1999; Yuill and Mikler 1995; Spitler et al. 2002) and limited horizontal space.  According to a paper by Mr.  Orio et al. in 2005 there were only about 1,000 standing column well-geothermal heat pump installations in the United States. Standing Column Well systems are groundwater heat pump systems that use groundwater drawn from wells in a semi-open loop arrangement. The ground heat exchanger in these systems consists of a vertical borehole that is filled with groundwater up to the level of the water table. Water is circulated from the well through the heat pump and back to the well in an open loop pipe circuit. The standing column can be thought of as a cross between a closed-loop vertical well system and an open-loop groundwater source system. The systems identified by the paper are in the colder climates of the northeast and west where air heat exchangers could not do the job, but a geothermal system can function in the extreme cold. In a survey of existing systems the most significant parameters were found to be well depth, rock thermal/hydraulic conductivity, and bleed rate.

During much of the year, the standing column systems operate by recirculating water between the well and the heat pump. The water is drawn from the bottom and returned to the top of the water column. However, during extremecold or hot periods they can “bleed” some water from the well to maintain thetemperature range of the standing column well by inducing groundwater flow into the well.  This causes groundwater to flow to the column from the surrounding formation to make up the flow. This serves to cool the water column during heat rejection in the summer, and warms the column and surrounding ground during heat extraction in the winter, thus restoring the well-water temperature to the normal operating range and improving the system performance. A bleed is especially important in the colder climates where the loss of temperature in the well could result in freezing of the system in extreme cold. In warmer climates an excess of temperature in the well during the hottest days would only result in a loss of efficiency since the temperature increase would still result in water significantly below the ambient temperature.

Most of the existing standing column installations are located in the Northeast and Pacific Northwest in heating-dominated residential and light commercial applications. The vast majority exist in the northeastern Appalachian region including Maine, Massachusetts, New Hampshire, New York, and the northwestern states. Because air heat exchangers have improved in efficiency so much in the last few years and the heating demands in Virginia and the rest of the south are much less than in the Northeast, ground source heat exchangers have been less popular in the south.

The home owner who contacted me lives on the Occoquan Reservoir right around the fall line in the coastal plain of Virginia, to be entirely accurate, the homeowner actually lives just west of the fall line and within the harder bedrock of the Piedmont. The Fall Line so named because the meeting of the Piedmont and Coastal Plain is marked by a line of waterfalls. The Fall Line is really a zone rather than just a narrow line. The rapids and waterfalls characteristic of the Fall Line extend up to a mile wide in some locations. The waterfall on the Occoquan River near Lorton has been "dried out" by the construction of the dam that created the Occoquan Reservoir, but still marks the line. You can see the exposed rocks at the Fall Line by walking upstream from the town of Occoquan when the path is open. The geology at the home is most likely a layer of generally unconsolidated, inter-bedded sands and clays, underlain by bedrock.

The homeowner’s well is 450 feet deep with the pump at 400 feet.  The well is probably that deep because that is what it took to find an aquifer just west of the Fall Line. That is not a good well for this water rich region of Virginia, but groundwater is not equally distributed throughout the region.  The water level in the well is about 35 feet from the surface creating water storage within the well of over 2,000 gallons.  The water storage has served to produce a consistent supply for the house since the well is reported to recharge at only 5 gpm- not really enough to run a household.  This is a non-robust aquifer and they drilled 450 feet to reach it. This well may indicate the difficulty of locating a well on the property or replacing the well if it is damaged. As a Virginia Master Well volunteer, my first reaction is always that the drinking water well is sacred and should not ever be risked especially in a location where there was difficulty with drilling a producing well. The homeowner is aware of this concern.

The groundwater aquifer recharges this well at 5 gallons per minute. This aquifer is not robust, even a 10% bleed at 0.6 gallons per minute would consume over 800 gallon per day. However, a bleed is not necessary. The thermal demands are not as high in Virginia as Maine and other parts of cold New England and the actual use of water by the household is probably 100-150 gallons a day. The use of the water for the heat exchanger is non-consumptive (it will be returned to the well at the 4-6 gallons a minute that it is drawn) and since the water in the well will turn over in less than a week and be constantly diluted with recharge, any impact from the metal portion of the heat exchanger should be negligible. The only true potential contamination would be a leak in the heat exchanger allowing the gallon or so of ethylene glycol to contact the well water and that should be carefully watched.

An important design feature to convert the existing well to a duel purpose well is the pump for the well will have to be replaced with a variable speed pump that can deliver at least 12-15 gallons per minute. A variable pump is needed because the pump will now serve two purposes. When the heat pump is operating it requires flow at 4 or 6 gallons per minute and the well must also be able to respond to the household needs an simultaneously pump to the pressure tank. There will have to be a duel switching system to trigger the pump. The heat exchanger has to be able to trigger the pump and lower demand when it shuts off and the pressure tank needs to be able to trigger the pump to either turn on or increase flow. There also has to be a valve trigger to open or close the valves to the pressure tank or heat exchanger.  Typically a standing column well needs to be 250-500 feet deep depending on the bleed. This well at 450 is perfectly sized for a 4-5 ton system and the recharge rate at 5 gallons per minute is really below the ideal level for a household, but this household has two residents so, their daily water demand is low.

The return line to the well should be buried at 6-8 feet below grade to reduce heat loss or gain when returning the water to the well. The return line should deliver the water within the water table in the well to avoid introducing turbulence induced mixing in the well column to allow the length of the well to provide adequate time for the temperature of the returned water to return to normal well conditions which for this well is about 50 degrees F. In addition, the homeowner will have to obtain an Underground Injection Control, UIC, Individual Permit from the U.S. Environmental Protection Agency, EPA. The EPA issues its UIC Permit under the Safe Drinking Water Act (SDWA), as amended, and implementing regulations at Title 40 of the Code of Federal Regulations, Parts 124, 144, 146, 147, and 148 and has some experience issuing permits for geothermal standing column installations in other parts of the country. In Virginia the EPA Region 3 manages the program and will walk the homeowner through the Class V permit process filling out the inventory data required for the homeowner. Their single requirement is a monitor to identify if there is a leak in the system coil that could release, according to the EPA, ethylene glycol into the homeowner’s well though they do not require regular reporting on the monitoring. The EPA representative explained that they are just trying to save the well owners from themselves. A Virginia Department of Health permit is not required, but plumbing permits are required on a county level.