HomeMy WebLinkAboutSTPUD_Water Pressure Model Letter_1139 3rd St_5_14_2026
Date: May 14, 2026
To: Derric Larson
Re: 1139 3rd St, South Lake Tahoe, CA 96150
Pursuant to your request, the South Tahoe Public Utility District (“District”) has prepared the following
information for use in your commercial sprinkler design calculations. You will need to consider all other
components downstream of the water main connection including, but not limited to, the extended
water service lateral, meters and meter assemblies, check valves, backflow assemblies, entrance/exit,
pipe and fitting losses, etc. Should you need the length of the service lateral from the main to the meter,
we recommend using the width of the right-of-way due to the unknown location of any future main
replacements. The flows and pressures shown on the attachment are an indication of the existing
system conditions at the water main during maximum day demand and do not include any additional
demands from your project.
The estimated static water pressure at your likely point of connection is 57 psi (assuming an elevation of
6283’ MSL at the meter location based on Google Earth). This static pressure is based on the low end of
a range of pressures calculated by a 72-hour maximum day demand extended period simulation
performed using the District’s hydraulic model.
Water flow estimates are provided from the closest existing District owned fire hydrant locations as
shown in Figure 1 on the attachment (FH #3246 and FH #3245). The flow estimates and associated
pressures are calculated using the District’s steady-state fire-flow model which has set parameters for
various pumps being on/off and may differ from the boundary conditions associated with the Extend
Period Simulation used to calculate the static pressure provided above. The model calculates the flow
estimates at a point on the pipe in the street at the approximate location of the fire hydrant lateral and
does not take into account any other downstream losses in the lateral, in the hydrant, etc.
The water model is an approximate computer representation of the actual distribution system and
should be field verified. Pressure and flow testing at existing hydrants and other locations in your
neighborhood is recommended to verify your system calculations. The District does not provide fire
protection engineering services and does not guarantee flow or pressure. You will need to engage a fire
protection engineer for your system design and have that person evaluate the model data provided
along with pertinent field data to properly design your fire protection system.
The above estimated information regarding water line sizes and water pressure (“Information”) is based
on the District’s currently available water system model, is provided solely in response to your request
for such information, and provided solely to assist you in planning for fire protection purposes in
connection with the development of your property. The water pressure and flows can vary significantly
depending on the time of day, customer utilization, water supply interruption, and water system
operational problems. The Information is provided “as is” without warranty of any kind, and the District
expressly disclaims all express and implied warranties, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose, and that the Information is accurate.
The District does not warrant, guarantee, or make any representations regarding the use of, or inability
to use, the Information in terms of correctness, accuracy, reliability, timeliness, completeness, or
otherwise. The entire risk as to the use of the Information is entirely assumed by you. Any person who
uses the information disclaims all liability for damages, costs and expenses and agrees that there are no
remedies against the District and its employees or agents for negligence, or for personal injury, breach of
warranty or contract, including but not limited to indirect, consequential, punitive or incidental damages.
The District will be reviewing parts of your project submittal as part of the City's review process. Please
contact our direct email at fireflow@stpud.dst.ca.us if you need additional information regarding
pressure or flows for your project. Review process, meters, connection details, inspection, fees, and all
other questions at the District should be directed to our Customer Service Department which handles
the permitting and inspection process. They can be reached at 530-544-6474.
Sincerely,
Megan Colvey, P.E.
Director of Engineering
South Tahoe Public Utility District
WATER SYSTEM MODELING BASED ON EXISTING MAX D AY 2014 WATER MODEL
Figure 1 –Schematic map of property location, closest fire hydrants and pipes nearest to service lateral
Table 1 - Steady State Design Fire Flow and Pressure
Elevation Above Pressure1 Connection to Main (gpm) at 20 Hydrant Connection to Main
1Static pressure provided at the hydrant is based on a steady state model of fire flow demands. This is not
calculated using the same operating conditions as the static pressure provided by the EPS model.
2Residual Pressure at FH #3246 is 70 psi
3Residual Pressure at FH #3245 is 23 psi
FH #3246
Assumed Point
of Connection
FH #3245
1139 3rd St