One of the most frustrating things about water restoration is getting a call from the adjuster saying your invoice is too high. Having been in the industry since 1992 I have gotten plenty of calls from adjusters saying that my price is too high on this dehumidifier or this fan, etc. This used to bug me until I learned the secret to prevent most of these calls, communication and documentation. Remember that the adjuster has to justify his work to his boss and as long as the price and scope of work can be justified then it will be paid.
Starting off the job on the right foot is important. You should always get a work authorization signed by the insured before starting work. A work authorization will allow some insurance companies to be able to pay you directly or at least get your name on the check.
Then as soon as the initial mitigation is performed, call the adjuster and let him/her know what you did. This can be done on the way back to your office. During this conversation just let the adjuster know what you saw when you arrived and what you decided to do about. During this conversation I generally try to steer away from talking about pricing. If they ask about it then I will talk about it, but for me this is more of an information phone call to the adjuster. At this point, usually the adjuster has not been there and so to call and inform him/her what is going on is my main objective.
Next, you should have an itemized invoice. The invoice should include your company name, address, (so they can send the check) and your Taxpayer Identification Number. Each room that work was performed in should be separate and have measurements down to the nearest inch. Then within each room list each item or piece of equipment. At this point it is good to comment on the items that are most questioned, such as cost of dehumidifiers, number of fans, extraction, etc. Place comments with the items, if your estimating software will let you, justifying why you charge what you do for a dehumidifier or why you had 3 fans in a 6 x 6 room. Anything that could be questioned comment on it. To me this is one of the most important parts of the invoicing process. Yes, it is time consuming but the adjuster will be able to see the reasoning behind the line item. This alone may prevent most calls.
Next include a copy of the signed work authorization and signed certificate of satisfaction. This not only shows that the customer was satisfied but that they authorized you to do the work. Make sure that your work authorization form includes a section in it that would allow the insurance company to be able to pay you directly. I, personally, had my lawyer look over my form to make sure it was accomplishing what I wanted it to accomplish. I would strongly suggest that you do the same no matter whether you got a generic form from somewhere or you came up with your own form.
Another tool that helps justify your bill to the adjuster is your daily humidity readings. You should be keeping the temperature, relative humidity, and grains (gpp) inside, outside, unaffected area, dehumidifier(s), and the HVAC. By doing this you will be able to learn about what is going on during the job. For example, several years ago we opened up a new refrigerant dehumidifier and took it straight to a job. When we got there and turned it on we started running our pshychrometric readings and discovered that there was a problem with the dehumidifier. It was great to find that out then and not the next day when we would have had a lot of evaporation and no dehumidification. Using the grain readings can also help you prove that the equipment was off, a door was opened that you wanted closed, a window got opened, etc. When this is used correctly then you can prove to the adjuster why you needed an extra day. Also make sure to include plenty of comments to go with your readings to help explain what you saw.
To go along with your daily humidity readings try including a graph from a data logger. Data loggers can be set to record the temperature and relative humidity as often as you would like. I like to set ours to record every minute and this gives you a good graph of what is happening on the job. When the job is complete then print the graph and turn it in with your invoice. Just like with your daily readings a graph will help prove what you saw happening on the job. (i.e. door left open, window open, equipment turned off, etc.) Taking an hour meter reading off your equipment at several points in the job can also help prove when things were not running and should be turned in as part of your documentation.