Expert: Dana Bostick - 7/6/2009

Question
My top floor Venice apartment is in a building that was constructed in the late 1920s. I know little about plumbing but can only surmise that even with the new toilet recently installed, the problem with water pressure and flow lies in the bones of the building. Humour me for a second, but my colon is a prodigious one and many a toilet is no match for the results. Therefore, I spend a few minutes everyday battling a toilet with a plunger. On a daily basis, this becomes quite a drain, ahem. The landlord installed a newer toilet, but it was to no avail. The water level inside the bowl does not rise very high and has actually lowered further on its own over time. Apparently it's a water efficient unit. What would you advise? Are there modifications that can be made to the toilet? It's been plunged and "snaked" repeatedly.
Appreciatively,
Silas

Answer
Hello Silas, (from a fellow SoCal resident, NoHo)

The water level in a toilet bowl is physically determined by the design of the bowl itself (the height of the trap weir) and nothing else.  It's "hard wired" in so to speak. It's actually called the "water spot" size. There is no adjustment that will change it. There is some adjustment of the amount of water that the tank dumps into the bowl during a flush, but not much.

For the water in the bowl to go down by itself there has to be a siphon being created by poor or restricted venting in the drain system.  

As water drains down the waste pipe after a flush, a siphon is created in the trap of the toilet which empties the bowl.  This is normal flushing action, it is the way it is designed to work. If the system is not vented properly or the vent is restricted in some way, draining other fixtures can create a siphon in the toilet that drains out the water because the system is trying to vent through the toilet bowl.

I think you are right, the problem is in the internal plumbing of the building somewhere. Finding it might be a bit of challenge.

Sometimes the vent lines need to be snaked from the roof. They could also be blocked by bird debris etc.

Good Luck,
Dana