The Lincoln Memorial Reflecting Pool on Washington's National Mall is set to be drained again for repairs after algae and peeling paint appeared just weeks after a $14.7-million US renovation, while U.S President Donald Trump threatened prison time for anyone caught damaging the pool.

The patriotic makeover of the historic Lincoln Memorial monument has gone disastrously wrong.

The water of the Reflecting Pool remained filled with algae, peeling paint as well as white blobs on Friday.