The advisory came in response to complaints from customers that the water smelled like ammonia.
Aqua says it has determined from water samples collected this morning that the water supply from that area contained elevated levels of ammonia.
Aqua says Ammonia is routinely used in drinking water treatment.
Aqua posted a water truck at the site of the Croydon plant (Cedar Avenue and River Road), where customers can pick up water until the advisory is lifted.
For more information, call Aqua Pennsylvania at 1-877-987-2782.