The City of Owatonna Building Inspection Division requires plumbing permits for the installation of Residential and Commercial irrigation systems (lawn sprinklers). These systems will require a final inspection to verify the installation of back-flow prevention devices at the potable water connection, proper pitch of the connection piping for drainage and the location of the backflow preventer for potential of back pressure on the back-flow prevention device (PVB, (SVB) & (RPZ).
** A Plumbing Irrigation system permit fee of $50.00 will be required for all residential installations and $100.00 for all commercial installations. **
A homeowner can install the irrigation system (backflow device, in-ground piping, heads, etc). If not the homeowner, then a licensed plumber is required to install, at minimum, the backflow preventer and potable water connection. The homeowner or a licensed low voltage technology contractor is required to connect any electrical wiring, etc.
The system must comply with the MN State Plumbing Code. MN plumbing code chapter 4715 section 2110 requires one of the following type backflow preventers on lawn, garden or greenhouse sprinkler systems:
Pressure vacuum breaker assembly (PVB):
- Must be installed at least 12 inches above spill line; (highest head that the system serves)
- No possibility of back pressure permitted; and
- Continuous line pressure permitted.
Spill-proof Vacuum breaker (SVB):
- must be installed at least 6 inches above the spill line; (highest head that the system serves)
- no possibility of back pressure permitted;
- continuous line pressure permitted; and
- field testable.
Reduce pressure Zone back-flow preventer assembly (RPZ):
- Any degree of hazard permitted;
- Back pressure permitted; and
- Continuous line pressure permitted
MN State law requires any newly installed system to have automatic rain sensor technology.
Owatonna Public Utilities has a Cross Connection and Backflow Prevention Program that must be followed also. Identification of the backflow preventer, location and annual testing criteria are required to be documented and submitted as part of their program. Please contact the Owatonna Public Utilities for all forms, specifications and documents at 507-451-2480; (fax: 507-451-3695)