Karl Townsend wrote:

It looks like my sewer and drainfield are very likely to be froze up when I
get home in a few days...

I own a hot pressure washer that I got from Northern Tool. They don't sell
the exact same model anymore but its very similar to this:
http://tinyurl.com/25qq5r

I'm planning on ordering 100' of hose and a sewer nozzle from these folks:
http://www.pressure-washer-parts.com...ozzle_hose.asp

I see the hose comes in three different sizes. Nominal 1/8, 1/4, 3/8. I bet
these aren't exact measurements. Nor are they NPT pipe sizes. (I've had the
wand off - IIRC, its a straight machine thread that tightens against a seal)

Those 1/8, 1/4 and 3/8 are almost certainly NPT sizes. What you have on
your pressure washer is most likely the metric 22mm coupling that is the
norm on most pressure washers I've seen. You likely need the 3/8" NPT
sewer nozzle and 3/8" NPT sewer hose, along with a 3/8 FNPT to 22mm male
adapter.

http://www.pressure-washer-parts.com/twistconnects.asp

A call to Northern could probably confirm the fitting you have, but if
it isn't the sliding sleeve quick connect (similar to the air quick
connects), and it's not a tapered NPT thread, it's almost certainly the
22mm metric fitting.

I think the female end of the 22mm fitting is normally on the hose side,
not the gun, but for the few dollars, you could get one of each adapter
from 3/8 NPTF to insure you have the correct end.