The advisory affects the 40,000 customers of Johnston County Public Utilities, who buys around 20 percent of water from Smithfield.
"They're having problems at their plant, so we're unable to purchase from them for a temporary period," said Chandra Farmer, of Johnston County Public Utilities.
With hot temperatures approaching, officials are asking customers to avoid non-essential water usage such as irrigation and filling pools.
"These are the uses that hit us hard, with those peak demand periods," said Farmer.
Water for drinking or production in business is considered essential.
The county said is closely monitoring the situation daily.
The shortage advisory may remain in place through Memorial Day.
"We appreciate our customers cooperation in helping us preserve the water supply, and we're working hard to have our normal supplies available as soon as possible," said Farmer.
Johnston County is also constructing a 2 million gallon per day expansion at the Timothy G. Broome Johnston County Water Treatment and said the additional capacity will be available in the next few weeks.
If you have questions, you can contact Public Utilities at 919-989-5075.
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