Shutdown could take .gov sites offline

"Given that websites represent the front-end of numerous back-end processing systems, agencies must determine whether the entire website can be shut down or components of the website will be shut down," the memo said. 

Public access to government information is not enough to justify continued funding for a website, according to the memo.

"The mere benefit of continued access by the public to information about the agency's activities would not warrant the retention of personnel or the obligation of funds to maintain (or update) the agency's website during … a lapse," the memo said. 

However, keeping some websites online could be critical. 

"If maintenance of the website is necessary to avoid significant damage to the execution of authorized or excepted activities … then the website should remain operational even if its costs are funded through appropriations that have lapsed," the memo said. 

For instance, the IRS website may need to stay online to allow for tax filings and tax collection, activities that continue during an appropriations lapse, according to the memo.

In that case, the IRS website would stay up, but the Treasury Department website would go down.

Agencies are instructed to shut down their websites even if the cost of taking it offline exceeds the cost of keeping it up.

"The determination of which services continue during an appropriations lapse is not affected by whether the costs of shutdown exceed the costs of maintaining services," the memo said.