Just curious how many of you are performing water heater draft tests as part of your home inspections? Is this necessary as part of the standards of practice for Nachi?
Thanks in advance.
Welcome Jason! I’m sure those that see many NG/LP fueled water heaters will chime in. I rarely come across one that is not electric in my rural area.
I never do unless there is a sign of backdraft. Even then if I were you I would just recommend evaluation by a licensed plumbing contractor.
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So then how do you check for excessive ‘EMPs’? 
Maybe I should have said, “fueled by electricity”… 
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Welcome to the forum, Jason Barrette.
Hope you are well and in good spirits today.
Great question. Keep them coming.
I use to preform several natural gas water heater drafts tests on all NG/LP water heaters, but now pick my tests as I see fit. Typically/normally mirror back drafting test but always preformed incomplete combustion hazards but slowed that test down. CO monitor runs throughout an inspection when NG/LP is used as an energy.
I use a lighter, smoke pencil and mirror. If I see signs of back drafting I sniff for incomplete combustion as well and sniff GN pipe connections.
Mirror is always at the ready. Look for fogging.
Great question for a new member. Keep up the great work and thanks for the reminder!
Best regards.
Robert
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I generally don’t but I do look very closely at the top of the tank for scorching/melting of plastic. There is a rabbit hole you can go down of powered vent furnaces sharing a vent with a natural draft water heater. When the furnace initially fires it pressurizes the vent of the water heater and causes temporary back drafting. This has been argued about endlessly on HVAC forums (yep, other trades argue too) but it’s still allowed by code/manufacturers, etc.
In my area it’s becoming pretty infrequent since nearly all of the furnaces have gone to 90+% end vent through the own PVC. I guess my point in all of this is that it’s possible to see some back drafting and it’s acceptable (for lack of a better term).
Appreciate all the replies!
I rarely check for back drafting. If there is combustion air sourced from the outside to the unit, back drafting is very unlikely.