Personally I’d charge nothing. Show your client the pictures and describe to them the conditions. Your health and safety is more important than inspecting (which theoretically you did not.) Your client will appreciate your honesty and respect that. You won’t lose them as a client.
The above is when I would have come to a meeting of the minds with the client or walked.
My health’s more important than money.
Maybe you could charge the client by the mount of time spent. I used to like to try to make $100/hour.
The client may have other places to inspect and you should know whether the utilities are on or tell them that you will inspect it in the condition that you find the utilities. And, that you do not turn utilities on…in any way, shape or form.
I always told and emailed my clients to make sure that the utilities are on. That makes it their issue or their and their agents issue. And, that I would inspect it in the condition that I found it for the agreed upon price.
A nod to Chuck Evans and Larry Kage they have some solid insight on this one. I have seen some real sweethearts in my short career. Some I knew were going to be bad and they ended up to be considerably worse than expected, also a couple that blind sided me. This can be a difficult discussion to begin at the time of the inspection. I have found that I can manage this expectation up front. In my agreement it states that my rates apply to a “habitable structure”. If you client reads the entire agreement (they probably wont), then this discussion can start early. If they accidentally overlooked that section of the agreement, you at least have a place to begin the discussion from.
You didn’t perform an inspection that complied with the SOPs, but that’s an unsafe home. Since you weren’t warned in advance you should charge something. Work it out with the client according to your time. If you charge $300 for a house that takes 2.5 hours you’re making $120 an hour. Give them a little bit of a break and if (!) they walk you’ll probably get their next house.