There could be a few reasons why there is water shooting up through the air vent of your dishwasher’s drain. If you have only recently had the dishwasher installed, the air vent itself may not have been fitted properly and may have become loose, causing water and other gunk to shoot up. On the other hand, if the dishwasher has been installed for quite a while and you have only just started to notice this problem recently, the hose from the air vent to the drain pipe may be blocked with food or other rubbish.
It could also mean that the housing draining system connected to the dishwasher has a problem and that could be blocked up. If you cannot find the problem yourself or do not feel confident enough in your DIY skills to fiddle with the dishwasher, call a plumber out as soon as possible to have a look at the problem.
The problem could also be down to an air vent that has not been installed properly or that has since become loose due to repeated use. Then again, if you have had the dishwasher for quite a few years, the problem may need to be resolved by getting a new drainage valve or hose. Your plumber should be able to advise you on what the best course of action is for you to take, depending on what is actually wrong with your dishwasher.
Alternatively, you may be able to consult the dishwasher manual and figure out the problem by having a look at it yourself.
Of course, it goes without saying that you should put off washing any dishes until you get the problem sorted, as nobody likes having dirty water all over their kitchen floor.
I had the exact same problem and fixed our by removing the vent line which you may find is also connected to your disposal or other drain...we pulled a bunch of gunk that had accumulated in the line over the past 7-8 years since it was installed. We just tested it and it drains into the disposal the way it always did...it is our Christmas miracle as tonight is Christmas Eve! Best wishes for a safe, healthy and merry Christmas..to Everyone!
Check the the hose from the air gap to the drain pipe is not blocked with gunk.
Rented the house? Tell your landlord. It's their problem to fix, not yours. If they tell you otherwise, consult your state landlord-tenant law.
I just put in a new air vent from ACE and having water back up problems like you described. Before changing the to the new air vent the vent worked fine but the owner wanted a new sink and fixtures. First time running the dishwasher (witch worked without leakage prior to replacing the old air vent) water running out from the air vent onto the counter and over the sink. My vent is non-adjustable and looks just like the new vents at ACE (thought maybe a faulty vent). Checked with my plumber and he could not find a problem with the system, except it over flows from the air vent. I put a hand soap dispenser where the air vent was and put flow through check valve in line under the sink where the air vent hooked into the dishwasher and garbage disposal (two different size hoses). Note: Never did come up with a solution as to why the new air vent didn't function correctly: Maybe it could not handle the volume of dishwater forced through the system, where the old one could? It doesn't make sense being the uniform codes have standardized most of these systems. .