Hi - I have been having problems with my kitchen sink draining extremely slow. If I put any chemicals down the drain, there is no effect. I checked the trap and it is clean. If I clear it with a plunger it works great, completely drains and runs great for about 30 seconds and then backs up again. I'm wondering if this could be an airlock. This drain is from an old farm house and I believe that it is just gravity fed out to our ditch. I'm not sure if this is related, but last summer, we had a leak around one of the drain baskets and I replaced it. Unfortunately, the local hardware store had a different depth to the one in stock that the one I replaced. So my lateral drain pipes are uneven. Could this be causing an air lock?

Hi - I have been having problems with my kitchen sink draining extremely slow. If I put any chemicals down the drain, there is no effect. I checked the trap and it is clean. If I clear it with a plunger it works great, completely drains and runs great for about 30 seconds and then backs up again. I'm wondering if this could be an airlock. This drain is from an old farm house and I believe that it is just gravity fed out to our ditch. I'm not sure if this is related, but last summer, we had a leak around one of the drain baskets and I replaced it. Unfortunately, the local hardware store had a different depth to the one in stock that the one I replaced. So my lateral drain pipes are uneven. Could this be causing an air lock?

It doesn't sound like a airlock, just a simple blockage. As a rule the blockage's found in the lateral, (the horizontal line in the wall). By using a plunger you're pulling the water back up the line from the blockage so it will drain back for a few seconds before it hits the blockage and backs up again. So actually you're doing no good at all.
The answer is to take the trap apart and snake out the drain line to clear it.
Good luck, Tom

We took the trap apart and snaked in 25 feet with no results, could the blockage actually be further out?

We took the trap apart and snaked in 25 feet with no results, could the blockage actually be further out?


How far does the drain line extend? If you didn't clear the line by going out 25 feet then the blockage has to be further out. Go for it! Tom