Thinking about a diesel pusher

Current diesel engines require a Diesel Exhaust fluid ( DEF) to be injected into the exhaust system to allow the engine to meet the Federal emission standards. Therefore, large MH's come with a separate tank to hold the DEF as it's automatically fed into the exhaust system to 'clean" the diesel emissions as they are released into the atmosphere. I believe this system was mandatory in 2010 (?) and the only way around having one is to purchase a MH prior that that year. To most it's not a big deal, just one more thing to take care of when you own a diesel MH. It adds a few cents to each gal. of diesel used but a gal. goes a long way. Most MH's come with fairly large DEF tanks so adding DEF is done only occasionally.