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First Flush Tanks are a cost effective solution to divert water in excess of 100 gallons for large Rainwater Harvesting Systems. Traditional methods of water diverting utilize PVC pipe. A 20-foot stick of 12-inch PVC will divert 100 gallons, but costs over $400 for the pipe alone. These tanks give you better value and look much more appealing. They are manufactured in our heavy duty weight for added durability and available in 13 different color options!

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100 Gallon First Flush Tank 100-Gallon First Flush Tank

30″D x 42″H

List Price: $262.37
Our Price: $204.95
You Save: $57.42
125 Gallon First Flush Tank 125-Gallon First Flush Tank

36″D x 50″H

List Price: $310.91
Our Price: $249.95
You Save: $60.96
150 Gallon First Flush Tank 150-Gallon First Flush Tank

30″D x 58″H

List Price: $344.95
Our Price: $274.95
You Save: $70.00
200 Gallon First Flush Tank 200-Gallon First Flush Tank

36″D x 56″H

List Price: $399.38
Our Price: $319.95
You Save: $79.43
250 Gallon First Flush Tank 250-Gallon First Flush Tank

36″ D x 67" H

List Price: $481.04
Our Price: $384.95
You Save: $96.09
500 Gallon First Flush Tank 500-Gallon First Flush Tank

48"D x 71"H

List Price: $776.15
Our Price: $619.95
You Save: $156.20
Standard Colors
SunShield Colors

Why use First Flush Tanks?

First Flush Tanks
If roof water is to be used for potable purposes or if roof contaminates will spoil rainwater (such as heavy bird droppings) then a first flush system will be needed. These devices keep the first wash of water out of your collection container. General rule of thumb for the discard quantity: 5 - 10 gallons per 1,000 square feet of roof or smaller. For larger roofs, discard 10 gallons per 1,000 square feet.
University of Arizona Cooperative Extension Water Wise Program, 2007 (PDF / 634 KB)

Our First Flush Tanks Feature:
  • Poly-Mart 5 Year Warranty
  • 100, 125, 150, 200, 250 & 500 Gallons of Capacity
  • Manufactured in Heavy Weight style for added durability
  • 1.5″ Bulkhead at the top of the tank for your Pipe Extension
  • 1.5″ Spin Weld Fitting w/ plug on the Bottom Flat for a drain
  • 3/4″ raised Spin Weld Fitting for easy Water Hose Spigot install
  • 4″ Inlet Fitting on a Top Flat for entry to the tank

Made from the highest quality rotational molded polyethylene our tanks are designed for above ground use.

*All Tanks of all colors are BPA-Free and manufactured with resin that complies with U.S. Food and Drug Administration regulation 21CFR 177.1520 (1) 3.1 and 3.2 for storage of potable water