President Trump said that his handpicked contractor would charge only $1.8 million to repair the Lincoln Memorial Reflecting Pool and paint it blue.

The actual cost is now more than seven times that, after the Interior Department nearly doubled the size of the contract late last week, federal records show.

On Friday, the Interior Department added $6.2 million to the contract’s previous cost, saying it now planned to pay $13.1 million to a Virginia firm called Atlantic Industrial Coatings. President Trump said he chose that company to repair the landmark because the firm had worked on the swimming pools at his golf club in Sterling, Va.

The government awarded that firm a no-bid contract last month, bypassing the requirement to seek competing offers by saying that the situation was so urgent that any delay would cause “serious injury” to the government. The government has not publicly said what that injury would have been.

Instead, it has cited Mr. Trump’s desire to get the work done before the country’s 250th birthday on July 4.

Public contracting records do not say why the contract’s cost increased so sharply on Friday. Katie Martin, a spokeswoman for the Interior Department, said that the higher price “reflects the effort necessary to expedite the timeline of completing the leak prevention coating project — more people, more materials, more equipment and longer hours ahead of our 250th.”

Atlantic Industrial Coatings did not respond to questions about the increase.

But government documents obtained by The New York Times show that the contract’s current value matches, down to the dollar, an offer submitted to the government by Atlantic Industrial Coatings in the middle of last month. That offer included a 20 percent profit margin, the documents show.

Competitive bidding laws aim to ensure that the government is getting a fair price from its vendors.

The contractor was hired to repair leaking joints between the pool’s concrete slabs, waterproof the pool’s bottom, and paint it a shade called “American flag blue.”

The pool has also been troubled for decades by leaks and algae blooms that turn its water green.

On Monday, a nonprofit dedicated to landscape architecture filed a lawsuit in U.S. District Court in Washington seeking to halt the paint job. The Cultural Landscape Foundation said that the Trump administration had ignored a law requiring advance scrutiny of projects that alter historic landmarks.

The foundation, based in Washington, said in its lawsuit that “every day that the resurfacing continues, the historic character of the Reflecting Pool is being further and fundamentally altered.”