When shopping for a house, many homebuyers overlook the sewer lateral that runs below the ground of a property. This is the pipe that carries wastewater from a home's toilets, sinks, showers, laundry and floor drains to the city or county sewer line.

It's an important pipe that shouldn't be ignored, according to Travis Pulsar, vice president of operations at HomeGuard, a licensed plumbing company certified in pipeline, lateral and manhole inspections.

This pipe can impact the environment and local waterways and can be costly to fix, so homeowners should take note of the condition of their property's sewer lateral, Pulsar said at recent Valley Association of Realtors meeting about sewer inspections.

Most sewer laterals are typically 3 or 4 inches in diameter and made from clay, cast iron or plastic. The pipe has two parts – the upper lateral, which extends from the home to the end of the property line, and the lower lateral, which extends from the property line to the public right of way or street, where it connects to the city or county sewer line.

Pulsar said a number of cities require sewer lateral inspections before a home can be sold. Regulations vary depending on the city. Costs and responsibility for repair or replacement also depend on the city.

In some cities, such as Morgan Hill, it is the homeowner's responsibility to maintain, repair and replace the entire sewer line.

In other cities such as Palo Alto, the homeowner is responsible for the repair or replacement of the upper portion of the sewer pipe that runs under their property, and the city is responsible for the lower portion in the public right of way. This means if the lower line is damaged, the city will repair it; however, if the problem is with the upper line, the property owner is responsible for repairs.

Homeowners in Palo Alto also are responsible for the general maintenance of the entire pipe that connects their home or building to the large city sewer main. This includes keeping the sewer cleanouts – the point of access where the sewer lateral can be serviced – accessible. Cities generally require two cleanouts on the property, one within 5 feet of the home and one near the property line, Pulsar said.

Palo Alto, Woodside, Mountain View, Menlo Park and many other Midpeninsula cities do not require sewer lateral inspections.

Pulsar said regardless of whether a city requires an inspection, it's a good idea to have one done before a property is sold so that sellers and buyers are aware of any potential issues that could arise with a home's sewer lateral pipe.

He said defects can result in wastewater seepage into the soil or overflow within the public sewage system. Damage may be caused by clogging, intrusive roots that can create cracks in a pipe, shifting or corrosion.

Pulsar noted the type of pipe used can make a difference. If a home was built before or around the 1960s, its pipe is probably made of clay, which is brittle and prone to cracking or breaking at the joints. Cast iron pipes were used in the 1970s. Plastic pipes were used in the 1980s and are the best and most long-lasting

"Fixing or replacing the sewer lateral is a very big and expensive item," Pulsar said.

Not every plumber can inspect a sewer lateral. Some cities only allow inspection by a firm that is certified.

Sewer line replacement typically ranges between $3,000–$6,000, but depending on the area, type of soil, length of the pipe and other factors, it can easily cost more than $10,000.

"It's a big-ticket item, so it's important to get ahead of that," Pulsar said.

Tips to keep your sewer line clean:

• Keep trees and bushes away from the sewer line

Trees and bushes that are planted too close to the sewer line can make maintenance difficult. Moreover, their roots can grow into the pipes and clog them and even destroy them.

• Avoid flushing wipes and other hygiene products down the toilet

Do not flush too much toilet paper or any paper towels, diaper or cleaning wipes, sanitary napkins and other hygiene products down the toilet. They can clog pipes and cause serious problems.

• Never pour grease or cooking oil down the drain

Avoid pouring cooking oil down the sink drain. Cooking oils like corn or vegetable oils will clog up your pipes and cause sewer line backups. Instead, place leftover cooking oil or grease in a sealed container and dispose of it as waste or recycle.

• Use drain screens in drains

Drain screens catch food scraps that the garbage disposal blades may not efficiently grind, including coffee grinds, eggshells, and potato peels. A drain screen can prevent them from going down your pipes and clogging up your drain lines. Place a drain screen on your shower or bathtub to avoid falling hair from clogging your pipes.

• Replace old clay pipes

If you live in an older home with clay or lead pipes, consider having them replaced with plastic pipes.

• Perform a maintenance rooter cleaning once a year

An annual rooter cleaning can help clear your sewer line of debris and anything else that could cause serious blockage.

Silicon Valley Association of Realtors (SILVAR) is a professional trade organization representing 5,000 Realtors and affiliate members engaged in the real estate business on the Peninsula and in the South Bay. SILVAR promotes the highest ethical standards of real estate practice, serves as an advocate for homeownership and homeowners, and represents the interests of property owners in Silicon Valley.

The term Realtor is a registered collective membership mark which identifies a real estate professional who is a member of the National Association of Realtors and who subscribes to its strict Code of Ethics.

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