"Pinhole leaks" are very small holes in copper water supply lines. If the leaking water pipe is visible, the evidence of an emerging pinhole leak is a green, wet area on the pipe. The hole may become larger over time, discharging a greater volume of water.
Water lines may run through walls, ceilings, and under concrete slabs. In those cases, leaks are not detected until damage occurs. The damage can be particularly severe when the leaks are hidden – walls and ceilings can collapse, studs can rot and floor coverings can be ruined. Mold can surface anywhere.
Additional damage may be caused if demolition is required to find and repair the leaking pipe. If the pipe is under the floor slab, then your friendly plumber will have to jackhammer through the slab to repair the pipe. The more difficult the leak is to find the more extensive the demolition.
In the Washington region, pinhole leaks are most commonly reported in homes located in Prince George’s and Montgomery counties, both served by the Washington Suburban Sanitary Commission (WSSC). WSSC claims that the cause of the leaks has not been determined but that studies are underway. Information is available on the WSSC web site. Point your browser to
http://www.wssc.dst.md.us/service/pinhole_charts.htm. According to WSSC, nearly eighty percent of the reported leaks involved homes built prior to 1970. The data is inconclusive since not all plumbers and homeowners report pinhole leaks to WSSC. Additional information and first-person accounts compiled by a Silver Spring resident can be found at http://www.washingtonareapinholes.com .This same problem has been reported in other areas of the country. A search on the World Wide Web will provide you with the sense that this is an increasingly common problem which is causing billions of dollars in damage. Once the cause is established, class action suits are sure to follow.
Many homeowners in nearby Carroll County also were experiencing the devastation caused by pinhole leaks. The County hired a consultant, Corrpro Companies, of Philadelphia, to investigate. Corrpro determined that the leaks were caused by a lack of calcium in the water. Calcium forms a protective scale on the inside of copper pipes. Based on recommendations from Corrpro, the County began adding caustic soda, an anti-corrosive element, to the treatment process last summer. Powell Laboratories, a Baltimore consulting firm hired by Carroll County residents, also determined that the leaks were caused by the water chemistry. Residents are demanding reimbursement by the County for expenses not covered under their homeowner insurance policies.
Currently, there is no known way for local homeowners to protect copper pipes from potential leaks. In fact, some homeowners have leaks repaired only to have new leaks occur. Some plumbers, and some jurisdictions elsewhere in the county, recommend CPVC rather than copper supply lines for re-piping and for new construction.
There are a few things that we can do to at least detect and limit the potential damage that pinhole leaks can cause:
Many of the Levitt homes in our subdivision are built on slabs. Supply lines run under the slab and then up the walls to the fixtures. If there is a leak in a line under the slab, the water will gradually find its way into the heating and air conditioning ducts running under your floors. You will see water in one or more ducts if you remove the register covers. It is essential that you turn off the water main, keep the air supply system as dry as possible by pumping out the ducts (to limit damage caused by high humidity), and find a plumber with proper equipment to find the location of the leak. The equipment consists of an amplified listening device that is run along the floor. A distinctive hiss will be heard over the leaking pipe. The equipment is specialized and costs approximately $2,000. If your plumber does not have this equipment, you might have more of a nightmare when he goes on an intuitive search with his jackhammer.