HomeMy WebLinkAbout018 - Water System Memo
cushingterrell.com
March 18, 2026
Development Review Engineer
City of Bozeman
20 E. Olive Street
Bozeman, MT 59715
RE: Ursus Major Water System Requirements
To whom it may concern,
The purpose of this memo is to address city code Section 38.410.070 – Municipal water, sanitary sewer and
storm sewer systems. The proposed project includes a domestic water and fire suppression service line.
Water Usage
Two methods were used to estimate the combined peak daily demand for domestic water use.
1. Utilizing guidance from Montana DEQ Circular 4, a typical flow rate of 13 gallons per employee per
day can be used to estimate wastewater flow. The same was used in this estimate for domestic water
use. With their 50 employees, the daily peak demand for domestic water use is 650 gallons per day.
2. The other method used was for the industrial wastewater / process water usage by comparing the
current usage of the existing facility as well as correcting for equipment advances and updates in
efficiency and was conservation methods. The total daily demand for industrial / process water usage
is 3,750 gpd. The irrigation system is expected to use 184,447 gallons per year with a peak daily
demand in July of 3,000 gallons per day.
Water Service Line Sizing
Service stubs from the municipal main have been provided into the subject property by the underlying
subdivision. There exists a 4” for domestic use and a 6” for fire suppression. Both of the proposed fire and
domestic service lines will be approximately 145’ in length from the water main in Royal Wolf Way to the
riser within the building, satisfying the maximum length requirement of 150’ allowed by 38.410.070.B.
Per plumbing code, the water system must be sized for peak demand based on fixture counts which is
estimated to be 90 gpm. The design pressure at the point of use is to be no less than 20 psi. Irrigation
demand will be from the domestic water service as well, however this will be timed to not coincide with the
peak building usage so this was excluded for this evaluation. Based on the fire flow data provided by the City
of Bozeman dated 1/23/2026, the static water pressure from the municipal system is 115.85 psi at the closest
hydrant (#3054). Considering the approximate head losses through 145 lf of 4” ductile iron (2 psi), backflow
preventer (12 psi) and the water meter (5 psi), the resulting water pressure is 96 psi which is above the 20 psi
minimum. At this time, no booster pumps for the domestic or fire system are anticipated.
Sincerely,
Adam Schlegel, PE