Monday, January 16, 2017

Whats in the Private Water Wells of Virginia

Because private drinking water wells serve more than a fifth of its population Virginia created the Virginia Household Water Quality Program (VAHWQP) to provide affordable water testing and education about private water wells to residents of the Commonwealth. Volunteers and Extension Agents hold drinking water clinics and provide information to assist private well owners in understanding and maintaining their wells. 

The quality and safety of private wells are not regulated under Federal or, in most cases, state law. In Virginia only construction and the absence of bacteria at well completion are required for a private drinking water well in the Commonwealth. The U.S. Environmental Protection Agency Safe Drinking Water Act cannot (and should not) regulate individual households. As a result, individual homeowners are solely responsible for maintaining their domestic well systems and for any routine water-quality monitoring that may take place.

The Virginia Household Water Quality Program was originally created in 1989, but was relaunched in 2007 with a USDA grant. In 2011 the program was expanded under another USDA grant to subsidize testing, quantify bacteria, add metals and begin research out of Virginia Tech. Now the program is self-sustaining with annual clinics in 60 counties. The analysis is done by the laboratory of Dr. Mark Edwards (a recipient of MacArthur Genius Grant and world expert on water chemistry) and research utilizing the data is being pursued by graduate students.

In Prince William County the Cooperative Extension office and the Conservation District hold an annual subsidized drinking water clinics for well owners as part of the Virginia Household Water Quality Program. As in all the clinics the water samples are analyzed for: iron, manganese, nitrate, lead, arsenic, fluoride, sulfate, pH, total dissolved solids, hardness, sodium, copper, total coliform bacteria and E. Coli bacteria, and last year cost $55. These are mostly naturally occurring contaminants and common sources of contamination: a poorly sealed well or a nearby leaking septic system, or indications of plumbing system corrosion. Though not an exhaustive list of potential contaminants, these are the most common contaminants that effect drinking water wells.

Though about 600,000 of Virginia households (22%) have private wells, only around 7,000 households have chosen to participate in the Virginia Household Water Quality Program clinics over the past 8 years and may not be representative of all private drinking water wells in the Commonwealth. Nonetheless, the data collected is the largest database on private drinking water wells available. The wells tested are an average of 25 years old and 72% are drilled wells, 13% are dug or bored wells, 5% are cisterns or springs and in 10% of the cases the owner did not know what kind of well they had. Eighty percent of the participants in the clinics had never tested their wells since the purchase of their homes (most mortgage lender require a bacteria test). Slightly over half (51%) of well owners had a treatment system, but the most common treatment devices were for aesthetic contaminants as can be seen below. 
from E. Ling VHWQP
Water quality tend to vary by location and depth. For example, in Floyd County in the Blue Ridge Mountains, the geology is crystalline rock with few fractures. This impacts water quantity and quality. The wells tend to be highly acidic and though they have low mineral content and total dissolve solids, these wells are likely to have lead and copper because the acidic water is likely to leach metals from the plumbing system. Northumberland County is the uppermost peninsula into the Chesapeake Bay with a geology of unconsolidated sandy sediments. Well water quality tends to vary by depth. Shallow wells are highly susceptible to nitrate and bacteria contamination from the surface and septic systems. Deeper wells are generally protected from contamination, but are highly saline from saltwater intrusion. Prince William County has an are within the coastal plain and a section in the Piedmont there are areas high in minerals with pockets of iron, manganese, and sulfur. For a complete list of county results see the summary

Overall the statewide sampling over the last 8 years has found that 41% of the wells have coliform bacteria, and 9% have E. coli bacteria. Though 28% of wells were found to have acidic water (low pH) only 17% of homes have first flush lead levels above the EPA safe drinking water standard maximum contaminant level of 0.015 Mg/L. Lead and copper leach into water primarily as a result of corrosion of plumbing and well components, but can also result from flaking of scale from brass fittings and well components unrelated to corrosion. Copper and lead do not naturally appear in groundwater and lead in drinking water is predominately coming from the pipes. Over time older pipes and fixtures corrode or simply wear away and the lead and other corrosion material (like rust) is carried to the drinking water. Time and water do cause corrosion, but this can be aggravated by the pH of the water or other changes in water chemistry. The amount of lead corroded from metal plumbing including faucets with brass interiors generally increases as water corrosiveness. For more information on lead in drinking water see here.

While 22% of households report having a water softener, only 15% of households had their water test as “hard” over 180 mg/L. This could be a result of some homeowners testing their water after treatment with a water softener or could indicate that water softeners are oversold for treatment of things like iron and manganese. At the water testing clinics we allow the participants to choose whether to test the water before or after any treatment devices (or both). Likewise, 29% of homes have sediment filters while only 7% of homes tested high for total dissolved solids. You might want to test your water to make sure it is safe to drink and you have the appropriate treatment system. Only 3% of homes had a treatment system for bacteria, though 41% of homes had bacteria present in their water.
from E. Ling VHWQP

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