Low-power Waterproof Ultrasonic

Does anyone here have some recommendations?

I'm looking for an ultrasonic sensor with a low quiescent current that is sufficiently waterproof (enough to handle some raindrops). It should preferably be either 3.3V or 5V.

I considered the MaxBotix sensors, but it may be a bit out of my budget as I prefer to keep it under $50 or so. I tested the JSN-SR04T, but wasn't particularly content with the results I was getting from it (a lot of measurements being all over the place) so I'm eager to try out something now

Lots of vehicle parking sensors on the market, with transducers intended for damp environments.