Got soaked through last week - lining wet as well.
Do you leave this task to dry cleaners or use a spray/DIY.
Coat in question is a poly cotton single breasted, fly front, raglan sleeve garment. I also have a trench coat that I might treat as well.
If it is machine washable, machine wash. Clean items repel water better.
There are wash-in durable water resistant treatments at most sporting goods stores, or one can spray.
I recently used a bottle of 303 High Tech Fabric Guard and it dried completely undetectable but seems to work perfectly.
http://www.amazon.co.uk/gp/product/B0000AY69N?*Version*=1&*entries*=0
It is dry clean. Scotch guard type spray might work. I do not see reproofing advertised these days though.