Is the purchase price already taking into account that the home needs further repairs, including replacing the main sewer line? If not (and the seller is unwilling to do those or reduce the price so you can) them I would probably move on and find something else. You’re realtor should not pressure you into moving forward unless it makes sense number wise - they should be showing you what homes without these problems are selling for and if the home is priced right, etc. Do you love the home, does it work for you and your family, or are you choosing it because of your timeline to find something? Good Luck with whatever you decide.