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 $US14.7 million ($A21m) renovation.
President Donald Trump has threatened prison time for anyone caught damaging the pool.
The DC Water authority issued a permit to drain the 609-metre rectangular pool, it said on Monday, while the repair company said it would fix the pool as part of its warranty.
