Pinhole
Leaks in
Copper Pipes
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Pinhole leaks in copper plumbing are a
widespread problem that affects property owners throughout the United States
and elsewhere in the world. Although much research has been conducted around
the issue, no definitive cause has been determined to date. As the leaks were
discovered in our area, Sarasota County Utilities was quick to establish a
local task force to research the problem and potential solutions. Task force
representatives include residents of affected housing developments,
professional engineers from Carollo Engineers and Sarasota County Utilities. To
work with the task force examining area issues and recommending solutions,
Utilities has engaged Dr. Marc A. Edwards of Virginia Polytechnic Institute, an
expert with 14 years’ experience conducting research in the field of copper
corrosion. That work has led Edwards to track pinhole leak occurrences in
Alaska, California, Massachusetts, Ohio, South Carolina, South Dakota,
Tennessee and Washington, D.C., as well as in Florida. Another expert we have
engaged is Dr. Edward Singley, a retired Professor of Environmental Engineering
from University of Florida, whose career included extensive research into
copper corrosion throughout Florida. As well, we have:
·
Conducted a survey of
plumbers to develop local/regional information on pinhole leaks. Plumbers
report pinhole leaks throughout southwest Florida in new and older homes.
·
Compiled historic water
quality data and supplemented it with additional water and pipe sample
analyses. Data analysis led to no specific indication of the cause of the
pinhole corrosion thus far.
·
Evaluated
alternative methods of corrosion control by researching case studies and
engaging other water utilities
·
Planned a
small study to determine if there is a correlation between pinhole leaks and
improperly grounded homes.
Although Sarasota County water quality consistently
exceeds strict federal quality standards, including corrosion control, we
remain committed to continuing our aggressive research of the problem and to
providing updates at this Web site on our progress in identifying causes and
solutions. A satisfactory resolution to
the pinhole leaks problem is a high priority for us. The following is a list of frequently asked questions that may
provide helpful background to our area residents:
Do pinhole leaks affect water safety?
Not
at all. The safety and reliability of County water is our highest priority. We
test constantly to ensure that the proper chemical balance is maintained.
Sarasota County’s water meets or exceeds all state and federal
standards/requirements.
What is Sarasota County Utilities doing about it?
·
We are
currently working with homeowners to identify trends and to develop possible
solutions.
·
We are
monitoring water quality and incidences of leaks tracked in representative
communities.
·
In November
2003, we converted to use of a phosphate corrosion inhibitor to optimize our
existing corrosion control program.
·
We have
engaged corrosion and water experts and are participating in a national
research project being conducted by the American Water Works Association
Research Foundation.
We are further investigating stray
electrical currents as a contributing factor in copper corrosion, as has been
suggested by numerous studies.
What is Sarasota County’s approach to corrosion control?
The U.S. Environmental Protection Agency (EPA)
requires that water utilities add safe chemicals to protect drinking water
supplies by prohibiting copper from pipes and lead from solder from leaching
into and contaminating the water. These chemicals act to form a scale that
lines pipes and prevents the release of copper and lead as caused by uniform
corrosion of metal pipes. Two common methods widely used by utility companies
in the United States employ carbonate or phosphate-based products to line the
pipes. The impacts on preventing the formation of pinholes by these methods are
not well understood. Until late 2003, our utilities system used a carbonate product
as a corrosion inhibitor at our Carlton Water Treatment Facility. This method
resulted in historically low copper and lead levels in our system.
Because some utilities systems similar to
Sarasota County reported reductions in pinhole-type corrosion after they
converted to a phosphate-based product, we switched to a phosphate-based
treatment throughout our
utilities system in November 2003. Sampling completed in September 2004 indicates the phosphate
inhibitor is successfully maintaining copper and lead levels at their
historically low levels, but there is presently no data to suggest a change in
the number of new pinhole leaks.
At the same time, we continue to explore
potential causes, other research and treatment options that are experiencing
positive results in other locations. Site-specific factors vary widely from
location to location, impacting potential success in addressing this issue. It is
significant to note that there is no requirement or prescribed treatment method
from the EPA or other regulatory body that addresses the prevention of pinhole
leaks.
What can
the homeowner do?
Whether installing new piping or
re-plumbing faulty pipes, it is important for homeowners to learn about their
material choices. Florida’s building codes permit the use of copper and plastic
pipe for plumbing. Homeowners and builders can determine which material to use.
Building grade copper pipe is available in three types: Type M copper has the
thinnest walls, and is often sold in hardware stores and plumbing supply houses
for residential plumbing installations. Types L and K copper have increasingly
thicker walls, cost more and may provide longer service life. Although copper
pipe has been used in plumbing for a much longer time and may be easier to
install, modern plastics allowed by building code are corrosion-resistant and
do not conduct electricity. Sarasota County does not recommend the use of one
material over another, but we do recommend that you research all available
materials to determine the best choice for you.
· If you are going to be away
for an extended period, turn the water off at your main valve.
· Periodically check the leak
detector on your water meter (blue triangle that spins) while no fixture is in
use; if it is turning, it may indicate the presence
of a leak.
If you see areas that appear damp or
water damaged, call a plumber.
What if I notice a leak?
If you notice a leak, contact a licensed plumber to identify the source
of the leak and help you determine what repair is needed to solve the problem.
Leaks are the homeowner’s responsibility, and should not be ignored.
One alternative to re-piping is an epoxy product that
is injected into copper pipes. The epoxy seals the pipe entirely from the
inside creating a pipe within a pipe. Examine all your options to determine
which is best for your home.
What else do I need to know?
Sarasota
County Utilities is collecting data relating to pinhole leaks. You can help by
providing us with information about your home, whether you have a leak or not.
The more information we are able to gather, the better base we will have to
help us to understand trends, to isolate or rule out conditions that seem to
favor pinhole leaks. Follow this link http://www.zoomerang.com/survey.zgi?p=U23ATSPYZ5JA
to a questionnaire that will capture your information.
If you do
have a leak, please provide us with as much information about the leak as
possible: location of the leak, whether
it was under the foundation slab, near a fitting, along a straight length of
pipe or both, whether the pipe is horizontal or vertical, whether the leak is
in a hot or cold water pipe. What type of copper is the pipe? Letters K, L and
M describe the thickness of the pipe wall. Type K is the thickest and type M is
the thinnest. Stenciled marks on the pipe often give this information. The
color used for the stencil should indicate type: Green (K), Blue (L), Red
(M). Has your house been unoccupied
(the plumbing unused) for an extended time?
If you can provide a section of pipe with a leak to Sarasota County Utilities, that could be
very helpful. Label the pipe with as much of the above information as you can,
and drop it off at 2817 Cattlemen Road, Sarasota.
You may contact Sarasota County Utilities Customer
Service at (941) 861-6790 if you have further questions.
NOTICE OF UPDATE
Since this article was published Sarasota County has
announced that on September 1, 2005 they added a new polyorthophosphate blend
into the Carlton Reserve water supply (serving south of Clark Road). According to David Cash, Sarasota County
Utilities Manager, the inhibitor prevents pinhole leaks from forming, and, for
the first time ever, extensive research shows it may even remedy existing
holes.
The results come from a long-term study conducted at
the University of Cincinnati’s Corrosion Office in conjunction with the
Environmental Protection Agency.
Source: Osprey Observer, October
20, 2005