Homeowners who are among the 110,000 customers of the Charleston Water System have been receiving solicitations for an insurance program endorsed by the utility, offering coverage of the water and sewer lines on customers' property.

Lots of people were probably surprised to learn they own a portion of their water and sewer lines, but, yes, they do.

Those lines, such as an underground waterline running from a home's foundation to the utility-owned water meter near the street, are the property owner's responsibility if they break. But does that mean it's a good financial decision to buy insurance in case repairs are needed?

You can buy insurance for just about anything. Some types of insurance are crucial because they protect against financial calamity that can be associated with things such as an expensive medical problem, a house fire or the death of a parent.

Other types of insurance cover things that are not very big financial risks, and the cost of the insurance compared to the potential benefit is typically high, such as with extended warranties offered on appliances. Waterline insurance can fall in that category.

That doesn't mean it's a bad idea for everyone. A person with a 50-year-old water service line, or an old clay-pipe sewer line, might reasonably consider buying coverage. Likewise, someone living in a subdivision where the neighbors' lines have been failing would have good reason to consider buying coverage.

For others, a good choice may be continuing to self-insure, which essentially means you don't pay for insurance, and you bear any costs if something breaks. Ideally, being self-insured means you have an emergency fund in case the unexpected does happen.

The bottom line is a cost-benefit question.

If water and sewer line insurance in the Charleston area cost $2.80 monthly, combined, as it does in Myrtle Beach, the low price would make it tempting to sign up. Locally, Mount Pleasant Waterworks is considering offering sewer and waterline coverage later this year, at an estimated combined cost of $4 a month.

The coverage offered to Charleston Water System customers costs $11.98 monthly for both water and sewer line insurance. Why so much more? One reason is, the insurance is offered not by the utility directly, but by HomeServe USA Corp., which signed a marketing deal with the water system.

Charleston Water System received $120,000 up front and gets 12 percent of the money HomeServe collects in premiums.

Here are some key points about that insurance:

The cost for the waterline insurance offered to Charleston Water System homeowners is $4.49 a month. Sewer line coverage is an additional $7.49 monthly. So, that's $143.76 yearly for both.

The average national cost of repairing a waterline leak is $416, according to HomeServe. Replacing an entire waterline could, however, cost several thousand dollars.

The water supply line from the meter to the home is all that's covered. Irrigation systems, water supply lines to outbuildings or docks, and interior plumbing lines are not covered.

The insurance does not cover repairs needed because of an accident, negligence or natural disaster. So, if your waterline breaks because you dug a hole in the wrong place, or someone parked a truck in the wrong spot, or because of a hurricane - no coverage.

Short of a line completely wearing out due to old age, the big threat to water and sewer lines in residential yards is tree roots. Otherwise, the estimated life expectancy of a waterline is about 50 years.

Someone with a long distance between their house and water meter, and a yard full of trees, would clearly face more risk of breakage than someone with 20 feet of water and sewer lines sitting beneath a grass lawn. So, evaluate your own risk before signing up.

Regardless of whether you have waterline insurance, every homeowner should make sure they know how to shut off the water supply to their house, in case an indoor pipe or fixture were to break.

That's a risk you can mitigate without spending money, by locating your emergency shut-off or your water meter, and making sure you know how turn off the flow.

Reach David Slade at 937-5552