Istvan-

Without more detail on valve and hydrant pressure class, connection
type, bury depth, soil conditions, etc.., I would say your best approach
would be to use a standard cost estimating manual such as Means.

As far as DIP laying lengths, and even valve and hydrant information, a
very useful text for you would be McWane' Pipe Economy. Call (205)
991-9888 to request a copy.

With regards to pipe failure, I am unsure of an equation to estimate the
probability of this occurring. You have to consider the mechanical
quality of the pipe, the installation techniques, and third party and
natural disasters. A good text for this is the Pipeline Risk Management
Manual written by Kent Muhlbauer.

Hope this helps.

Brad Castleberry
bcastleb@hdrinc.com