[hatzie]

It's worth pulling the reserviour out and filling with water where you can observe. Won't hurt anything to drive around without the tank in place while you wait on parts.

The HDPE washer reserviour was not where my washer was leaking but I have seen them cracked and leaking so I bought a Dorman tank. It fits well enough. Used works as well as new as long as the used tank isn't leaking.

My low washer fluid sensor and pump were both cracked and leaking. The pumps are common enough that NAPA had Trico pump in stock. The level sensor was an online acquisition.

The other place these leak is the washer fluid hose.

Trico makes decent quality pumps that come with a brandy new tank gasket.
You can machine a chunk of HDPE or Delrin or some other plastic to plug up the port where a cracked low fluid sensor goes or replace it with a new AC Delco sensor.

I would wipe a film of Sil-Glyde or some other di-electric grease on the electrical plugs and plug gaskets with an acid brush to keep the salt water and brine out of the connectors.