You'll have to try to isolate the noise. Yes, the washer definitely will interfere especially if you don't have an external antenna with a screened feeder. Next time you hear the noise, go and see if the washer is running, take the radio with you and find all the other noise sources, TV's, satellite boxes, cable box, light dimmers, WiFi and routers, switch mode power supplies, the list is endless, then you can start worrying about the external noises. Some of them are data transmissions, usually military. I have one near me on 4250kHz that is so consistent I use it as a performance test! Sounds like a large truck going uphill (STANAG?) and it's S8 day and night 24/7.