Basement Rough-in Leak Test

[NCDIYr]

I have a question about rough-in leak test and how long the drain pipe system filled with water should realistically maintain the 'full level'. Our plumbing code only requires pressure be maintained for 15 minutes and "the system shall then be tight at all points." I've let the drain pipes sit for days and have needed to refill the drain system with a half gallon of water per day.

I do not see any visible water on the basement floor around the PVC pipes, coming out around the shower pan (that's also filled with water), nor in the empty basin that has the 4" pipe capped off. The water must be leaking under the concrete floor. Is this ok for the long term? Maybe small leaks under the concrete just peculate away.

The code only requires 15 minutes of no leaks, so that must be the average length of a shower ?!?

Thanks in advance for the Advice!

 

[johnjh2o]

How high is the stand pipe that you're flooding the system too? It should be at least 10' if not you're not putting enough pressure on it.

John

 

[NCDIYr]

John, the pipe is just over 3' or so above the sink trap. The code has an exception for 1 and 2 family dwellings that calls for, 'a minimum of 3 feet above the highest drainage fitting.'

 

[johnjh2o]

If you're loosing water you have a leak. Any leak no matter how small is not acceptable.

John

 

[Caduceus]

On a rough-in leak test you could also drain the water down and refill with water while adding liquid powder dye...as long as there is no risk of staining finished surfaces. You would have a better chance of seeing a leak and looking into the site tee, building trap or clean out downstream to see if a test ball is leaking through.