Water damage restoration work is a specialist area , and requires an investment in equipment and training, like anything else, I know that carpet cleaners traditionally got involved in this becuse they have tranferrable equipment meaning that the set up costs are lower than starting from scratch, eg extraction machines ,, blowers ,, sprayers etc.
This is exactly how Chem-dry got in to waterdamage restoration , I know I was with them from 1993 when they started to get serious.
I now do 95% damage restoration work by £ turnover. In my area is Sheffield shaun ,, who with his TM and van probably has the same amont invested as me in equipment ,, and we probably earn about the same too ,, so its horses for courses really .
To be serious about making a living from water damage you really need about 30-40 good new dehums and about the same in fans,, about 3k in training ( national flood school) ancilliary kit .... meters, foggers,, sprayers chemical stocks about 3-4k . i t is not a small investment , however it can be lucrative.