If you got one, you've got a whole bunch.

[frindle2]

Hello. What does the underlined sentence mean in the context below? Does it mean 'if you have one chipmunk, you have a bunch of problems'?
Thank you.

The man is going on about his problem with chipmunks in his cellar. "They're cute until they chew through your wires. Now I don't think about cute. I think about that electrician's bill. Darn little pests. If you've got one, you've got a whole bunch."

Source: Rules by Cynthia Lord

 

[Rover_KE]

Does it mean 'If you have one chipmunk, you have a bunch of problems'?

No — it means 'If you have one chipmunk, you have a lot of chipmunks'.

They congregate in groups/families.

 

[teechar]

It means: if you see one, the chances are you have more than just one.
See Rover's answer above.