The Port Hueneme Water Agency is at the end of the line when it comes to the drinking water it receives from the United Water Conservation District’s Oxnard-Hueneme pipeline.Because of the ongoing drought and out-of-service wells, the water received from United has degraded in quality. Port Hueneme’s Brackish Water Reclamation Demonstration Facility can no longer filter it without causing long-term damage to its system.The levels of manganese and iron in water pumped from standby wells are so high they are choking and destroying expensive filters, officials say.