If you have the option to completely disconnect your sprinkler system from the city’s culinary system because you have both secondary and culinary water, I am now offering a service where I would dig down to your stop & waste valve, remove it, and install a compression coupler.  I would also remove your backflow assembly and the piping that supports it.  This would satisfy the city’s requirements so that you would no longer need to have a backflow assembly, thereby eliminating the cost to have it tested yearly.  

My price for this service would be $400. 

As always, if you found a lower price for the exact same service, I would beat that price by 5%.