Copper Pipe In-Ground Problems

Grounding Corrosion

• Copper pipes provide the ground for home electrical systems, but the connection between the copper pipe and the grounding clamps can corrode the copper pipe if the grounding clamp is made from iron or steel. Corrosion of the copper pipe will eventually cause a leak that can go undetected underground for months before you notice a problem. If possible, use a nearby galvanized steel pipe for grounding electrical wires instead of the copper pipes.

Freezing

• Copper pipes carrying water can freeze in the winter if they are not buried deep enough. The depth for burying copper pipes will depend on the frost depth in your region of the country. Copper is an excellent conductor of heat and cold, and freezing temperatures in the soil around buried pipes can be conducted to the water inside the pipes, causing the pipes to burst. Prevent this by burying your copper water pipes deep enough so they will not freeze.

Joints

• Using sections of rigid copper pipe underground can increase the chances of leaks because each part has to be jointed. The joints create weak spots in the line where water can seep out. To avoid creating a slow underground leak, use long stretches of soft copper pipe, available in 60-foot lengths, instead of 20-foot sections of rigid copper pipe, according to Peter Hemp in "Plumbing a House." Like grounding straps, joining copper pipe to steel can create corrosion of the pipes through electrolysis. To avoid this, use dielectric unions. These connectors have a plastic spacer between the two halves so the different metals from the pipes do not touch.

Solder

• Lead used in soldering of copper pipes, especially in older systems, can leach lead into the water supply, according to "Design of Water Resources Systems" by Patrick J. Purcell. For copper pipes installed under the ground, without digging up the line, you cannot see whether lead was used for the solder. Test your water for lead and consider replacing your underground copper water line with new pipe soldered with silver instead. Another alternative is to let the water run for a few minutes before using it, as recommended by Tom Tynan in "Home Improvement with Tom Tynan: Homeowners Most Often Asked Questions." This flushes out lead that leached into the water from standing in the pipes. Water filters designed to remove lead should also be used.