Why does Columbia have so many boil water advisories?

Columbia’s water department has issued over 100 boil water advisories for the past two years straight, and is on track to match that number again this year.

That might be a good thing.

Columbia Water, the water provider for almost 400,000 people across most of Richland County and parts of Lexington, issued 112 water advisories in 2021 and 111 in 2022, according to Benjamin Wildt, spokesperson for Columbia Water. The utility had 53 advisories in 2023 as of July 12.

By comparison, Charleston and Greenville didn’t issue any advisories in that same time.

But those numbers might not be as concerning as they seem.

Columbia Water issues an advisory anytime a section of pipe has to be closed off for repairs or construction, Wildt said. Advisories are then lifted after the repaired section has been flushed and water samples indicate the water is safe.

While the number of pipes that have to be isolated for repairs in Columbia’s system is normal for a city of its size and age, the number of advisories issued in the state capital is much higher than other comparable cities, he said.

That’s because Columbia Water has a policy of being more “transparent” with customers about water line activities than other utilities, Wildt said. This policy has been in place since at least 2005, he said.

“(Boil water advisories) are issued by Columbia Water for circumstances that other utilities would not make any kind of public announcement,” he said.

Chlorine in the system prevents bacteria from contaminating the water when pipes burst, and system-wide testing is done on a monthly basis, Wildt said. Even so, the utility still issues advisories as a precaution anytime there is a drop in pressure in a pipe.

A boil water advisory is issued by a utility when the water in the system may be contaminated, according to the state health department. A boil water notice, by contrast, is issued when the water is proven to be contaminated.

While Columbia Water averaged two advisories per week in 2022, the department has not issued a boil water notice in the past two years, Wildt said. The last time the utility issued a boil water notice was April 14, 2021, after a E. coli was found in pipes along Gadsden Street. The notice was repealed the next day and subsequent testing indicated the original test may have been a false positive, he said.

Before that, the last notice was issued in 2012, he said.

In both advisories and notices, customers are advised to boil the water from their tap for one minute before using it, according to Columbia Water’s website. Alerts for advisories and notices are posted online and on the water department’s social media pages, and they are sent to local news outlets. Customers can sign up for text message alerts on the water department’s website.

Notices should be issued when there is a threat to public health, such as when testing shows chemical or sewage contamination in a drinking water system, according to the state health department.

Advisories are issued when the contamination is possible but not proven. They might be warranted if a failure at a water treatment facility allows untreated water into the system, if pressure is lost to part of or the entire system, if a line breaks and might allow dirt into the system, if water from an untested source is used in the system during an emergency or as a precaution in preparation for a hurricane, according to the state health department.

Boiling water is only suggested when there is bacterial contamination in the water. A chemical contamination means the water should be avoided all together, according to the state health department.

Using water that hasn’t been boiled during a notice can cause illness, whereas advisories are often issued as a precaution, according to the health department.

Columbia Water issues advisories anytime pressure is lost in a section of pipe in the system, Wildt said. This most often happens when a pipe bursts and has to be repaired, according to the Columbia Water website.

Losing pressure in a water main can allow bacteria to enter the pipe and the water, said Susan Richardson, a chemistry professor at USC specializing in drinking water.

While Columbia is on track to issue more than 100 advisories for the third straight year, advisories issued in other major cities in the state pale in comparison.

Charleston’s water department last issued a notice in 2022, and last issued an advisory in 2019, Mike Saia, spokesperson for Charleston Water System, said. The system has had a total of three advisories and one notice since 2015.

Greenville Water issued one advisory in 2018 and hasn’t had another one since, spokesperson Abby Weinshenker said.

The three systems are relatively similar in age – Columbia and Greenville’s oldest pipes date back to 1900, Charleston’s to 1880. Greenville’s system is the largest by miles of pipe, with over 3,100 miles compared to Columbia’s 2,400 and Charleston’s 1,800. Each serves between 400,000 and 500,000 people, with Charleston’s service population being the largest.

Wildt could not provide examples of instances where Columbia would issue an advisory when other utilities would not.

“We would not presume to speak for other utilities, this is an observation on our part of how other utilities handle this issue,” he said.

Unlike Columbia, Charleston Water does not issue an advisory each time the city has to repair a leak in a pipe, Saia said. He said the system probably has between 100 and 150 line breaks in a year without issuing an advisory for nearly all of them.

Charleston usually keeps water pressure up while repairing sections of broken lines, and therefore does not need to issue an advisory, he said.

Likewise, Greenville also keeps lines pressurized while work is ongoing, Weinshenker said. Greenville’s system is kept pressurized by gravity as water flows from the mountains rather than by mechanical pumps, so the system doesn’t often lose pressure at all, she said.

Greenville’s system has around 65 line breaks a year, Weinshenker said.

The state health health department requires public water companies to issue boil water notices when the system is contaminated, but the standards for advisories are more open to interpretation, Laura Renwick, spokesperson for the health department, said.

“For advisories, the ‘may be contaminated’ clause leaves it to the discretion of the water system provider for issuing an advisory,” she said.

While the health department is required to be notified when a water system issues a boil water notice or advisory, the agency doesn’t officially track them, she said.

Wildt said around 50% of Columbia’s advisories are issued when a pipe bursts on its own with no outside influence. Around 40% are scheduled outages for construction and 10% are caused by third party damage, such as construction crews accidentally drilling into a line, he said.

The age of the system is to blame for the pipes bursting on their own, he said.

The pipes under downtown Columbia date back to when the system was created around 1900, Wildt said. Parts of the system further away from downtown tend to have newer and more durable pipes, he said.

“Thus fewer water main ruptures from aging infrastructure issues,” he said. “The outer areas tend to have more construction, though, so that is a factor there.”

A majority of the advisories issued between July 2022 and July 2023 occurred in and around downtown where the older pipes are, according to data from Columbia Water. The St. Andrews area also received multiple water advisories during that time, due to several water mains being relocated during road construction, Wildt said.

While Wildt estimated 50% of Columbia’s advisories are caused by old pipes bursting on their own, Saia said around 90% of Charleston’s broken lines also happen with no outside influence. Weinshenker estimated 95% for Greenville.

Boil water advisories caused by the age of systems is a common problem in cities across the country, Richardson said.

“(The number of spontaneous breaks), that tells you – aging infrastructure,” she said.

Columbia Water has “an ongoing annual Capital Improvement Program to address needed water system improvements due to aging infrastructure, changes in regulations, and system growth,” Wildt said.

Columbia Water spent over $4 million in 2021 and 2022 on pipe repairs, he said. So far in 2023 that number is just under $2 million.

Columbia’s budget for the 2022-2023 fiscal year set aside $13 million for improvements to the city’s drinking water system, down from $40 million the year before. The proposed 2023-2024 budget allocates almost $29 million to drinking water improvements – less than 1% of the city’s overall budget.

Columbia Water expects to spend $15 million on system improvements in the 2023-2024 fiscal year, Wildt said.