have 1979 rabbit with fuel injectors?

If you can hear the pump, that means the relay and and wiring are good at least.

But the filter could easily be clogged with water.

The pump could also not build up pressure, so you need to check it in the engine compartment, with a gauge. You can get a gauge and adapter kit at Harbor Freight for $30.

If the pressure is ok, then pull the injectors out of the manifold to watch them spray. They are just nozzles, and not electrical. But pull carefully, not on the line, and wiggle as you extract them from their rubber O rings. Use new rubber O rings later. For starting there is a 5 injector that is electrical, connected to the starter solenoid. You can hot wire that to get it to run in order to ensure the spark and fuel is good. If that works, then it is the fuel distributor or the injectors are clogged.

The fuel distributor can be removed from the case fulcrum box, but so not split the halves of the fuel distributor block. It has fine shims and springs you will not be able to put back together. But if you remove the whole black block from the silver casting, you can check if the piston in the center is free or stuck. You can clean it, remove any rust, and soak it to clean the micro slits.

With the rubber plenum off, you can lift up on the folcrum plate, and you should see the injectors spray, if the pump is on. Look for bad injectors spraying unevenly, dribbling, leaking, clogged, etc.