TomC wrote in
:

"EXT" wrote in
anews.com:


"Blattus Slafaly" wrote in message
...
Chris wrote:
Steve Barker DLT wrote:
when they do mine, it's empty when they leave.

s

"pat" wrote in message
...
How much liquid should be left on the bottom of a septic tank
after being cleaned 1", 2" or more?




Odd, the fill mine with water after pumping the sludge out. The
tank could be damaged if left completely empty, I am told.

You were told a lie.

A light weight plastic or metal tank in a high water table area might
want to float if it is not weighed down with plenty of soil
overburden or full of water.



In 2004, when building my new house, the 1500 gal.two chamber concrete
septic tank and line was installed but not backfilled. A tropical
storm came through and dumped about 2" of rain. The empty tank floated
and turned over in the trench. The installers broke it while trying to
right it and had to install another. So, it doesn't matter what their
made of it all has to do with water displacement in a confined space.

Yea, displacement is the defined key to floating but you really can't
say it doesn't matter what it's made of. A lighter object must displace
less water to float. Dunno what a septic tank weights but if it weights
a ton it must displace the amount of water that weights a ton if I
recall.