Plumbing in the Home/Toilet Bowl Water Level

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Expert: Cortez (cort) Cate - 6/8/2005


Question
Maryland.

American Standard Toilet, made in 1937.  Over a period of hours, the level in the bowl mysteriously drops to a level below normal.  How can this happen?  Doesn't the trap hold the water level constant?  The other two toilets in the house do not have this problem.  No sign of any leaks from porcelain.

thanks.

Answer
Hi Eric,

If you have time to look at some of my responses to questions there was a similar one to yours just last week.  

Your water closet is quite old and just about anything can happen.  One of the main problems with age is the buildup of calcium that can take place in the bowl waterways.  

When the level in the bowl drops relatively quick it is usually a problem that is solvable with an auger or plunger; something may be lodged and the trap needs to be cleared.  Your situation sounds more like a leak in the trap but who knows for sure.  The only way to tell for sure, if the auger and plunger does not help is to remove the bowl from the floor flange and test the bowl for cracks or a hole in the trap.  

To do this you simply remove the assembly from the floor flange, it is easier to take the tank off first and you will want to install a new tank to bowl kit when you reassemble.  After removal you want to turn the bowl upside down and inspect the trap for visible obstructions or damage (hole or crack in water way of trap) but you can not see the entire distance without using mirrors and a flashlight.  Next set the bowl in the tub or shower and fill the bowl with water to the proper level.  If the water level goes down now it has to be leaking and the obvious solution (for a 70 year old water closet) is to replace it with a new one.  Still repair is possible if you can find the leak.  If the water level does hold then you must have an obstruction in the closet bend or the vent that is causing the bowl to continue its siphoning action after the flush.  If that is the case you need to check the vent and closet bend making sure the closet bend (the closet bend is the section of pipe that the floor flange connects to and it conducts the waste to the main drain line usually within a couple of feet and at the main drain there is a vent connection) will take at least 15 gallons of water (using 5 gallon buckets pour directly down the closet bend) quickly without backing up.  If it backs up or there is a lot of noise you need a plumber.
Good Luck,

Cort

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Cortez (cort) Cate

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I can answer most questions related to residential and commercial plumbing for buildings up to ten-stories in height. I have excellent knowledge of the UPC and UMC. When I am not sure of the best answer or exactly what you want to know I will at least let you know what I think and try to give you realistic options. Many problems are unique and have no simple answer. In those cases I will try to give you some guidance and you should use that to refine the question further and we, together, can seek the answer via a follow up. Plumbing codes and practices vary around the world--If you don't tell me where you live the answer I give may not fit your locality. I no longer seek ratings for my answers and my time. I am giving my time to you as a way of fulfilling my perceived obligation to share. All the volunteers here deserve the highest rating all the time for their efforts to help and share. Many of you will not take the little time to say thank you; that's ok, it is not required. I am here to try to help you find a solution to your problem. If my answer solves your quest for knowledge that is great and you are welcome BUT most often I will merely be pointing you in the right direction and giving you a little knowledge boost to help you find your answer. REMEMBER, If you want a good answer you need to ask a detailed question and include where you live, type of pipes, type of building, water pressure if it is a water problem, type of heater, age of appliance & building all these and many more are variables that have an effect on various situations. We can't give you a good answer without good information.

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Since 1972 a California licensed B-1 General Building Contractor, C-36 Plumbing and C-16 Fire Sprinkler Contractor; also installing and servicing Heating, Air Conditioning and Sheet Metal operating as C and C Building and Plumbing, California State License 279516. In 1995 I downsized the company to become semi-retired. Still I remain active in the construction industry. As head of a company I placed personnel and job safety as the number one objective followed closely by training and continuing education. Always seeking to stay informed of leading edge technology in the industry. Also I have spent several years as an Apprenticeship Instructor in the Pipe Trades Unions. Additionally I am a certified OSHA instructor.

Education/Credentials
United Association of Plumbers and Steamfitters Instruction Training, Ann Arbor, MI Bakersfield College, Bakersfield CA Cal Poly San Luis Obispo, San Luis Obispo, CA Foothill College, Los Altos, CA California Licensed Contractor from 1971

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