Date: 201908
Local time of day: 0601-1200
Location: RNO.Airport, NV
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Aircraft component: Drinkable/Waste Water Syst
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Flight Attendant In Charge
Reporter qualification: Flight Attendant Current
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Flight Attendant (On Duty)
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Passenger Misconduct; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Passenger; Person Flight Attendant
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We had just done the main cabin door shut announcement; started our compliance checks. Aircraft was in motion backing out of gate area; when non-rev passenger from XXA yelled out to non-rev passenger XXD to move to her open seat next to her. So non-rev passenger XXD moved as I'm telling her no and shaking my head still she continues to move back the seat in XXC. I met up with the non-rev passenger as she sat down and informed the non-rev passengers that I will have to tell the Captain that you have moved seats and this might cause a delay. Told Captain and he said OK and the flight went on normally. Sterile light came on and made announcement for final walk through the cabin. A parent was waiting for his child to exit the aft lav. Child came out and told me that the sink was spraying so I looked and the water in the sink was coming out of the faucet on the mirror and back wall. So I reached over to turn the knob when it fell off the wall and water came shooting out of the wall at me and I tried to cover the spray with my hands but I was overwhelmed and the spray started to heat up. Shutting the lav door to avoid the water. Made a loud noise and started flowing like a river out of the bottom of the door. I instructed my other Flight Attendant to call the Captain. I opened the galley bins with the napkins and towels that we have and threw them on the floor but the water was to overwhelming and the landing gear was down. The water overflowed into the aisle and 6 rows of seats; as the plane tipped forward the water became a river and made its way down the aisle I saw passengers' bags in their laps to avoid the water and had said over the PA that a stream of water was making its way to the front of the aircraft. The water made its way to the cockpit door and the whole front galley was in water. We landed and the fire alarm had sounded in the aft galley. The Captain called and asked my other Flight Attendant to check the back lav to see if there was smoke in the lav. She had checked and said yes. Captain instructed me the take a second look and I went rushing down the aisle; opened the lav door and looked in to see that the water was not shooting out as bad as before and that there was steam and no smell of smoke. I told that Captain and we were headed to the gate. I sat back in my jump seat in the front and I called my Flight Attendant and instructed her to grab the fire extinguisher if an electrical fire were to break out during deplaning and check the lav periodically to see if the steam dissipated. We arrived at the gate and started to deplane. The disruptive non-rev passenger decided to block the aisle at the main cabin door to tell me how unprofessional I was when they had moved seats earlier to sit next to each other. Captain asked her to move so that passengers could exit the aircraft due to the damage and not knowing if a fire would break out. She decides to lean into the front galley to inform me that she used to be a flight attendant and her niece is a flight attendant with [Company] and will be informing her of the mistreatment that I had done to her. I told her she jeopardized her safety along with other passengers' safety when she decided to move during the taxiing of an aircraft; she walked away without any other word. All passengers deplaned safely. Passengers' child detected the leak. I and other flight attendant saw as well and it went from there.


Second narrative: I was in the aft galley with FA (Flight Attendant) A when 2 PAX - a dad and daughter - came up to use the restroom. The daughter was the only one who went in. When she was in the restroom the FO (First Officer) came on the speaker and began his initial descent announcement. FA A began his initial descent announcement right when the FO finished. Right as FA A finished his announcement the daughter comes out and mentions to her dad and myself and FA A that the sink isn't 'turning off'. We tell them we will see what's going on and they can take their seats. FA A went into the restroom with the door open and we both observed water spewing from the faucet and spraying the windows. FA A went to turn the nozzle when the whole nozzle came off and the sink water came out shooting like a cannon. FA A took the damage of the water and we immediately closed the door to prevent it from hitting the back row passengers. After closing the door we could hear a loud whooshing of water coming out of the sink that the aft passengers realized what was going on. I picked up the phone and called the pilots to let them know what was going on while FA A tried to get napkins to stop the water from leaking to the rows but the stream was coming too strong. Since we were already descending to ZZZ FA A and I did final compliance checks before taking our jumpseat. That's when I noticed the aft lav smoke detector was sounding off and the pilot called quickly to ask if I could identify any smoke or odor coming from the aft lav. I opened the door and the lav had a fog to it but no odor. FA A quickly came over to double check and we determined no smoke was happening from any electrical failure but was the steam from the hot water that the sink is capable of since the aft lav smoke detector would turn off after a couple of rings and then turn back on when a few minutes passed. As we approached landing I noticed the water was starting to slow down but still flooding. Once we landed the pilots called once again to make sure no electrical fire was happening since the aft smoke detector was still going off and I kept checking to make sure no fire was happening as we began to taxi to the gate. I take out the halon just in case but did not break the seal. We get to the gate and deplane with no more further incident.


Synopsis: EMB-175 flight attendants reported that in addition to an unruly passenger while boarding; there was a malfunction of the AFT lavatory sink; allowing water to flow forward to the cockpit door.