A house in Houston, TX (southern "sun belt" climate, no frost, but flexible clay soils) has a Polybutalyne supply line running from the meter to the house. It's already burst once and been repaired, but the homeowner is considering replacing it entirely before it fails given that the repaired portion showed signs of the well-known flaking and fracturing problems that Polybutalyne has become known for.

What is the best material, given the climate and shallow depth, to replace the pipe with? It's not a long run, so copper is possible, but are PEX and CPVC candidates? What are the expected lifetimes of the different types of pipes and what are drawbacks?

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    HDPE is common as a supply line here, and our soil is all clay. – Jay Bazuzi Sep 29 '11 at 22:24

Copper (Copper)

At about $20.00 per 10' 3/4" ($2.00/ft), may be the most expensive option. Depending on soil conditions, drainage, and bedding material used around the pipe, copper can corrode.

Copper info.

CPVC (Chlorinated Poly Vinyl Chloride)

3/4" schedule 80 CPVC will cost about $15.00 per 10' ($1.50/ft), slightly cheaper than copper and can be easier to work with than copper. CPVC is a hardy material, and should have no problems in any soil type.

Plastic Pipe and Fitting Association FAQ (CPVC).

HDPE (High Density Polyethylene)

3/4" HDPE will cost about $45.00 for 100' ($0.45/ft), so depending on the amount required can be much cheaper than the previous options. HDPE is used by many municipalities as water supply lines, so it has been tried and tested in underground applications.

Plastic Pipe and Fitting Association FAQ (HDPE).

PEX (Cross-linked Polyethylene)

3/4" PEX runs about $40 for 100' roll ($0.40/ft), so again depending on the amount needed it can save some money. There are mixed reports about using PEX underground. Some people suggest installing the PEX in a conduit (PVC/CPVC) to protect it (which raises the cost), while others report it can be directly buried without a problem.

Plastic Pipe and Fitting Association FAQ (PEX).

In all cases you'll want to make sure the pipe is buried below the frost line, and follow proper procedures for burying the specific material (depth, bedding, etc).

Both Copper and CPVC will require more fittings (depending on run length) than HDPE or PEX, but for short runs they may actually be cheaper to use. PEX and HDPE both come in rolls and are flexible, so they can be easier to work with than a rigid material. Depending on the run length HDPE seems to be a cheap, easily installed, reliable choice.

Make sure you check with your local government for rules and regulations before making the final decision, and always Call before you dig.

Estimated prices provided by Google Product Search, at the time of posting. Prices may vary over time, and by location.

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