I rent an apartment and it has a submersible sump pump. It used to make a boom noise when it would go off. I got used to that. It became normal. That's what the pump sounds like. For the past 3 weeks it hasn't made the boom now it makes a buzzing drawn out noise. My boyfriend cleaned the outside of the pump and the basin its in and it still sounds loud and the humming isn't any better. Should I be prepared to buy a new sump pump? Or how can I fix the problem.

Why are you considering buying a pump when you" rent " an apartment. That should be the landlords job.

Because I am renting from a friend and they are coming across hard times. The pump was replaced last year. I just want to know what I have to do to fix the issue as cheap as possible.

I have looked on YouTube and a few other resources. I feel like I am responsible because it was replaced while I have been staying here. I fear waking up and my apartment being flooded. I would like to fix it so it isn't a burden on my land lord.

I just want to make sure we are talking about a sump pump, not an ejector pump. The "boom" noise is most likely the check valve closing on the output pipe. Is the pump running more frequently? If so, you may have a piece of trash in the check valve and water is running back. If the frequency of pumping is the same, you may have a piece of trash in the impeller. You can remove the check valve and look inside as well as removing the screen off the bottom of the pump and look for something caught in there.