Does a nutrient agar plate work ok for growing water bacteria?

I'm doing a science fair project on what method of water purification works best to treat water of harmful bacteria, by counting the growth of colonies on an agar plate. My teacher doesn't have any R2a agar plates, only nutrient agar plates, and they're very expensive to buy online. I was just wondering if a nutrient agar plate would work ok, to save time and money.