How Long Will PVC Pipes Last Underground?

You can use different materials suitable for underground water and sewage pipes. The goal is to choose the best option available to prevent possible costly repairs. If you are a homeowner and plan to install or replace existing pipes, you should definitely consider PVC pipes.

The key questions are how long will PVC pipes last underground, how high quality are they and how much do they cost. Experts estimate that the lifespan of these pipes is at least a century, as those installed three or four decades ago show no visible deterioration. You should only check that your installations are suitable for PVC pipes before you buy. See.

PVC pipes

Many households use convenient and durable polyvinyl chloride (PVC) pipes to:

  • High pressure applications
  • Sink, shower and toilet drains
  • Primary water supply lines
  • Vent stacks

Their huge advantage is protecting water from rust and preventing sediment from forming inside a smooth inner liner.

Since these pipes can withstand high water pressure, you can use them as the main water supply pipe or house sewer pipe. This lightweight material is easy to handle and can last practically a lifetime if it does not suffer serious physical damage.

Unfortunately, you can only find PVC pipes in limited sizes, and this material cannot withstand too hot water.

Despite the fulfillment American National Standards Institutestandards, there is concern about toxicity and possible introduction of polyvinyl chloride chemicals into drinking water. Therefore, the laws of some states prohibit the installation of PVC pipes for the transport of drinking water.

How long do PVC pipes last underground?

How long do PVC pipes last underground?

Convenient, durable, and inexpensive PVC pipes appeared on the American market in the 1960s, but their widespread use began in the 1990s. They usually come in opaque, white, and gray options. People mainly used them for water supply lines as an alternative to expensive materials prone to corrosion.

No one can say how long PVC pipe will last underground, but experts estimate that a lifespan of up to 100 years for drain lines is a fairly realistic possibility. For now, they are known to last over 50 years. However, their lifespan depends on their specific use, while some causes can shorten this period:

  • Incorrect installation
  • Inadequate insulation in winter
  • Tendency to become brittle over time

Fortunately, there are several things you can do to prevent damage to PVC pipes. Once you decide to install them underground, you should determine exactly how deep to bury them.

It will be sufficient to check your local law and ordinances, regulations and codes and follow local pipe laying techniques to prevent pipe damage. The procedure includes:

  • Inspection of pipes for scratches, nicks, cuts and split ends and rejection of damaged ones
  • Digging a trench of the required width and trying to make it as narrow as possible with wider pieces for pipe joints
  • Provide a required depth of 12 to 18 inches (30.5 – 45.7 cm) below the maximum freezing level for pipes susceptible to freezing
  • Placement of permanent lines at a minimum coverage of 24 inches (61 cm)
  • Ensuring the installation of the pipe system capable of supporting the daily loads

It is essential to take care of winding pipes smaller than 7.6 cm in diameter. Serpentine pipes compensate for the thermal contraction and expansion of pipes when installing them on a hot day. Therefore, you should take care to let it harden and dry properly.

Finally, you should carefully inspect the fixing pipes in the morning when the shrinkage stress is minimal. Be sure to support them along their entire length on a stable base to prevent possible damage.

Characteristics of PVC pipe for use underground

Characteristics of PVC pipe for use underground

Typically, PVC pipes used for household water and sewer systems are 8 to 12 feet (2.4 – 3.6 m) long, with 1.5 inches (3.8 cm) in diameter. The best way to connect them is with couplings, primer and cement.

Wall thickness

Note that you should choose specific pipes depending on their purpose. They usually come in three different wall thicknesses:

Although you can use all three programs at maximum temperatures of 140 F (60 C), the 40 pipe program is the best option for home sewer lines. On the other hand, the 120 program is an excellent option for industrial applications.

Schedule 120 pipes are the thickest and strongest and can withstand the highest pressure. You can quickly recognize those with different program numbers by color. For example, 40 schedules are white, while 80 schedule pipes are gray.

Pressure tolerance

Pressure tolerance is specific to each pipe program, as each can withstand a certain amount of pressure depending on its diameter. The pressure rating range indicates the force the pipe can tolerate per square inch of surface area and is given in PSI (pounds per square inch).

40 Pressure tolerance of PVC pipe

Pipe sizePressure rating
0.5 inches600 PSI
0.75 inches480 PSI
1 inch450 PSI
1.25 inches370 PSI
1.5 inches330 PSI
2 inches280 PSI

PVC pipes have precisely determined pressure levels suitable for residential underground system. For example, the nominal pressure range for different programs is:

  • 120 to 810 PSI for schedule 40
  • 210 to 1230 PSI for schedule 80
  • 380 to 1010 PSI for the 120 program

Advantages and disadvantages of PVC pipes

Advantages and disadvantages of PVC pipes

You can see many advantages of PVC, while the disadvantages are often related to improper installation.

Pro

  • PVC pipes are durable, flexible, safe and will not rust over the years
  • They are resistant to chemicals, microorganisms and corrosion when placed underground
  • This material neither reacts chemically with water nor affects its taste and smell
  • Installation is effortless and requires little material use
  • They require little maintenance
  • They are a cost-effective option

Versus

  • Improperly installed PVC pipes are prone to cracks and leaks
  • Inadequate backfill can result in damage from large, hard stones and clumps
  • Pipes buried above the frost line will freeze

Other residential plumbing pipes Lifetime

Other residential plumbing pipes Lifetime

On the market you can find pipes made of many materials. The best water supply option are those made from:

On the other hand, the best solution for drain pipes are:

Located underground PIPES lifetime

Pipe materialLife expectancy
PVC pipes70 to 100 years
Cast iron pipes70 to 100 years
Copper pipes70 to 80 years
ABS pipes70 years
CPVA pipes70 years
CPVC pipes50 to 75 years
Orangeburg Pipes50 to 60 years
Galvanized steel pipes50 to 60 years
PIPES PEX45 to 50 years
Brass pipes40 to 70

Cast iron pipes

These pipes are usually gray in color and are a standard option for drain lines in older homes and buildings. The main use of cast iron underground pipes is in the sewage system and they are inconvenient for water supply because this material is prone to corrosion.

Old pipes also have a problem with clogging often, making them impractical and unhealthy. These heavy pipes can last 80 to 100 years when properly placed underground.

Copper pipes

Because copper is prone to oxidation, these brown pipes sometimes take on a greenish hue on the surface. They are an excellent option for water supply lines in commercial buildings and still exist in construction built after the 1950s.

Their estimated lifespan is over 50 years, but quality pipes can probably last 80 years if installed correctly.

Brass pipes

These bright yellow pipes are not widely used, but you can sometimes see them in residential homes. Their average lifespan is about 40 to 70 years.

CPVC pipes

CPVC (Polyvinyl Chloride) pipes can withstand high temperatures and pressures, making them an excellent option for above and below ground use. In most cases, you can expect them to last between 50 and 75 years.

PEX pipes

Durable and flexible PEX pipes have become a common choice for residential homes since the 1980s. You can often tell the difference between red lines for hot water and blue lines for cold water, but they also come without these markings. Their average lifespan is about 40 years.

Galvanized steel pipes

Dark gray or black galvanized steel pipes are typical for houses built before 1950. Their significant disadvantage is rot, which always comes from the inside to the outside, causing water impurities.

Even though they can last about 50 to 60 years, you should replace these pipes after about 20 to 30 years. Only in this way can you prevent negative effects on human health.

Lead pipes

These dull gray colored pipes are rare nowadays and you can only find them in older houses built from 1800 to 1920. After this period, their installation in homes was prohibited. The crucial problem was that they were prone to scratching, severely affecting the water.

summary

PVC is a cheap and widespread material used for water and wastewater distribution nowadays, due to its many advantages and long life. It is durable and resistant to chemicals, microorganisms and external and internal corrosion when placed underground.

Some estimates show that installing PVC pipes can reduce repair and maintenance costs by 93%, so you can expect this material to replace others within a few decades.