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Rainwater Harvesting System
Operating Instructions & Parts Manual


Designed and Installed by Senior Biosystems Engineering Students:
Nicolas Koontz
Bryan Kohart
Hunter Hicks


System Diagrams
Components and Functions
Operating Instructions
System Capacity
Recommendations & Maintenance
Water Flowchart & Related Calculations

System Diagrams
(Click on images below to see detailed diagrams.)

Overall Diagram close up diagram of rainwater collection system Distribution Diagram
Overall Diagram Close-up Diagram Distribution Diagram

Components and Functions

.5 HP Centrifugal Pump Dayton 3YU60 $130 Grainger
One-Way Valve PVC $5 Any home store
Diaphragm Tank Dayton 4MY61 $250 Grainger
Cistern ------- 1550gal Polyethylene Water Tank $700
Float Switch Dayton 3BY76 $105 Grainger
Pressure Switch 30-50 PSI Square-D 9013FSG-2J21 $20 Grainger
First Flush Device FloTrue K300-W-M $30 FloTrue

Operating Instructions

System Capacity

The pump will flow a maximum of ~3.7 GPM at 40 psi. The pump is setup to operate between 40-60 psi.

Cistern-Storage Tank
The tank has a maximum capacity of 1550 gallons. Due to the location of the outlet port and float switches, the maximum usable capacity is ~1350 gallons. The water usage/storage data is tabulated in Table 1.

Table 1-1 Year Results Average Rainfall

Average Rainfall Total Collected Usage Amount of Water Stored @ End of Month Lost Water
Month (inches) (gallons) (gallons) (gallons) (gallons)
January 5.00 5984 0 0 4434
February 4.90 5864 0 0 5864
March 5.60 6702 2,000 1550 4702
April 4.3 5146 2,000 1550 3146
May 4.1 4907 2,000 1550 2907
June 3.9 4667 2,000 1550 2667
July 5.0 5984 2,000 1550 3984
August 4.8 5744 2,000 1550 3744
September 3.5 4189 2,000 1550 2189
October 3.7 4428 2,000 1550 2428
November 3.6 4308 2,000 1550 2,308
December 5.1 6103 0 0 6103
Totals 53.50 64025 18000 44475

*Rainfall Data from derived from NCDC Cooperative Stations (1911-1995)
The table indicates, there approximately 44,475 gallons of surplus water each year. This water will be directly dumped on the ground through the drainage system. Table 1 assumes that no water will be stored during the winter months.

Recommendations & Maintenance


  1. Do not go into tank without supervision and use caution when in tank to avoid drowning
  2. Disconnect power supply before servicing system
  3. Make sure manual cistern drain valve is closed when system is powered
  4. Plug in float switch as indicated in diagram, between electrical supply and pump cord
  5. In case of large storm, take ball/spring out of first flush
  6. If water begins to collect up the flume, drill more drain holes
  7. Do not attempt to raise line pressure above 60 psi. Serious injury could result.


Water Flowchart & Related Calculations

Click the following link for the water flow diagram pertaining to the calculations and considerations below. (flow chart [PDF])

Related Calculations/Considerations
How much volume for year will be coming through the system? Distribution throughout the year?

Can Flumes handle volume? Will grate/funnel work? Required fittings? Redo existing flume.

3a-First Flush:
How much flush is appropriate? Setup orientation of First Flush device

How big based on needs? Foundation for tank

Setup of overflows to drainage

Type, capacity, price, specs of pump based on use needs

Setup of system after pump, Create possibilities for wash-table and irrigation that will be convenient for installation

Volumetric needs, continuous or on-demand, tie table drain to system drainage

Vegetation type, rough area, plant needs, get through drought time, possibly xeriscaping

Drain to where, what type of drainage can overflow be routed to irrigation for ground dispersal? Must go away from building, tank, and refrigerator

Maintained by: Kelly A. Gilkerson    
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