When I replaced my hot water heater, my neighbor asked me if I g

Sea Isle City - When I replaced my hot water heater, my neighbor asked me if I got charged a permit fee by my plumber .When I told him I didn’t, he said his plumber got a permit because it’s the law and I could be fined up to $2,000 dollars. I called the plumber and told him I maybe selling my house and it could come out in the inspection paperwork that I didn’t get a permit he said not to worry about it, it won’t affect the sale. Does anyone know who would inspect and fine me and if the plumber is right.