Interesting question since typically inspectors don't come back for the final walk-through (AKA: Final Verification of Property Condition). Since there is a known water issue and extended stay it may make sense to have that repair inspected after it is done. This is basically a visit to satisfy yourself on the condition of the home after any repairs are done and that the property is in the condition you expect it to be in. This walk-through is not a contingency or condition of the sale.
The issue I see is if this re-inspection is done after the close you have less recourse. I would rather the repair and re-inspect be done before escrow closes. If re-inspection is difficult due to schedules or ?? you can ask the seller to leave money in escrow until the repair is re-inspected. Whether you re-inspect or not you should decide what information will satisfy you regarding the repair. The seller should provide you or your Realtor with receipts for this and any other repairs, on that receipt will be the company or person that did the work and what work was done and the cost. Call the plumber and discuss the job if needed.
Good luck and congratulations on your new home,
Brian Wilson, Realtor
If the seller is going to fix things...you might first suggest that the seller and listing agent meet you at the walk through and go through the repairs together. Have them be the ones to show you what was done. Also, ask for receipts from the workman with contact information so you have recourse.
If you do have an inspector come back, he should not charge you another $400. I've had inspectors come back to check repairs for $100-$200.
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Keller Williams Realty
On the other hand, I'm sure you are requiring some evidence of repair (ie: an invoice from a local plumber showing that the repair has been made)... and a call to the person who made the repair could put your mind at rest.