Septic tank on a single family home

Hi, I am a current property manager, and I used to work in the septic pumping business. Make sure you ask how old the system is, if it is in compliance with the town, and when the last pumping service was. As others stated, millions of homes have septic systems. Yes, they can be costly to repair or replace, however the systems do last a long time and as long as you are providing routine maintenance to it, you should be fine. 

What you could do is ask for a system report from a septic company that you choose. This way there would be no conflict of interest. Any septic company can come out and assess the lifespan of the system and what maintenance may be needed now or routinely. Only if any issues are found now would you need to involve an excavation company to assess. 

I do advise that you pay for the routine pumping services yourself when you place tenants, but factor that into your rental price. I would also place in the lease not to flush items such as wipes, feminine hygiene products, paper towels, or anything other than toilet paper down the drains. The life of your septic system is going to be the last thing on a renter's mind.