your best bet is to fill it up all the way, then wipe everything down dry and just wait and see

mine was leaking in the area I tried to highlight. the rubber o-ring wasnt doing its job so I loaded it up with vaseline and problem solved

I have had 2 separate leaks on mine. One was a bad pump, as others have stated, easily fixed.

The second failure was from a plastic L shaped nipple that connects to the reservoir. For this I employed a free fix-simply got rid of the L shaped nipple, and connect the rubber hose directly to the reservoir. Just make sure that your hose doesn't kink when you reinstall and you are good. Most vehicles washer reservoirs simply connect directly to a rubber hose, with no plastic nipple.

You can order them on Amazon.

OES Genuine Washer Pump Grommet with Strainer for select BMW models : Amazon.com : Automotive

Look into the washer fluid container and see if the leakdown is to the pump input. That will verify it is the pump or pump associated. If not, you should be able to fill the reservoir up and apply some air pressure which will expose the leak.

I fixed my leaky tank by applying Teflon tape to the grommets that the pumps go into. I probably should get new grommets but for now this has worked. I would start here first before replacing the pumps.

thank you for all your great ideas!