# Calculate Gallons Of Rainwater Collection From A Tarp

UPDATED

When it rains, there is a stunning amount of water that falls from the sky, and it adds up very quickly for every square foot that you capture and collect from water runoff (as from a tarp).

For survival and preparedness, or for the purposes of simply collecting rainwater for various uses including drinking or irrigation, having a method of capturing the rain will provide you with a large quantity of free water.

Here’s how many gallons of rainwater you can collect based on some examples of various tarp sizes and the amount of rainfall:

One great prep item is an ordinary tarp (lots of uses). Even a small 5×7 foot tarp can collect a-lot of rain! For example, by using a few lengths of cordage, tie up the tarp corners to some tree branches (or use support poles -sticks), slope the tarp downwards, and form a ‘V’ such that any rainwater will channel to one runoff point (into your container). Even from just 1/10 of an inch rain, you could collect nearly 2 gallons of water with that small tarp!

Most rain events are less than 1 inch. I’ve calculated several scenarios to illustrate how much rainwater is available for collection based on several different tarp sizes (their square footage) versus the amount of rainfall.

(2) 5×7 Tarp
(3) 6×8 Tarp
(7) 9×12 Tarp
(9) 10×14 Tarp
(12) 12×16 Tarp
(17) 14×20 Tarp

(5) 5×7 Tarp
(7) 6×8 Tarp
(17) 9×12 Tarp
(22) 10×14 Tarp
(30) 12×16 Tarp
(44) 14×20 Tarp

## Gallons Of Rainwater Collection From 1 Inch Rain

(22) 5×7 Tarp
(30) 6×8 Tarp
(67) 9×12 Tarp
(87) 10×14 Tarp
(120) 12×16 Tarp
(175) 14×20 Tarp

Let’s say you set up a rainwater collection system for the roof of your house (adapting to the gutters), and let’s say that the roof footprint is 28×40 feet. A 1-inch rain event will yield an incredible 700 gallons of water! That’s enough water to (minimally) support two people with drinking water for nearly a year!

The point being that it doesn’t take much to be able to collect lots of rainwater. By keeping an ordinary small tarp in your kit, you will not only have the ability to make a simple shelter, but it will provide the ability to capture valuable water if you need to.

TECHNICAL CALCULATIONS

14.44 cubic inches per cup (a fact)
1728 cubic inches in a cubic foot (12 x 12 x 12)
119.7 cups per cubic foot (1728 / 14.44)
7.5 gallons per cubic foot (119.7 / 16)

Example: 1 tenth inch of rain on a 10 by 10 foot surface

CONVERT SQUARE FOOTAGE: 10 x 10 = 100 square feet
CONVERT INCHES TO FEET OF RAIN: (1/10) / 12 = 0.0083 feet
CALCULATE CUBIC FEET OF WATER: 100 x 0.0083 = 0.83 cubic feet
CONVERT TO GALLONS: 0.83 x 7.5 = 6.2 gallons

Related Posts That You Might Like:

#### 30 Comments

Modern Survival Blog is a Top Prepper Website

1. FredLewers 07/22/2014 2:17 PM
2. Peanut Gallery 07/22/2014 6:37 PM
3. tango 07/22/2014 7:44 PM
4. T in TX 07/22/2014 10:27 PM
5. Syberdogpa 07/23/2014 8:21 AM
6. notalone 07/23/2014 9:52 AM
7. grey lady 07/23/2014 10:22 PM
• Sgt Bill 07/10/2015 4:22 PM
8. Adrian 07/26/2014 9:33 AM
9. Sysiphus 07/09/2015 10:56 AM
10. Look&lern 07/09/2015 11:55 AM
• Ken Jorgustin 07/09/2015 12:18 PM
11. Panic 07/09/2015 1:26 PM
• NRP 07/09/2015 2:01 PM
12. RWT 07/09/2015 1:53 PM
• Vewy Vewy Quiet, 07/09/2015 3:46 PM
13. NRP 07/09/2015 4:37 PM
• Ken Jorgustin 07/09/2015 6:37 PM
• Vewy Vewy Quiet, 07/09/2015 6:46 PM
14. Otarn 07/09/2015 7:14 PM
15. No joke 07/09/2015 8:30 PM
• NRP 07/09/2015 10:25 PM
16. Bizzarre Concept 07/09/2015 11:02 PM
17. CaliRefugee 07/10/2015 4:44 AM
18. Mike K 07/10/2015 6:20 AM
19. Sysiphus 07/10/2015 11:18 AM
20. otterwalks 07/10/2015 9:26 PM
21. dan 07/11/2015 6:59 PM
22. Ken Jorgustin 07/13/2015 6:39 AM
• NRP 07/13/2015 11:02 AM
Vote for MSB -Top Prepper Website

By commenting you are agreeing to our:
Policy & Terms of Use

For Off-Topic discussion:
Latest 'Weekly Preparedness' post

The most recent from ALL articles:
RECENT COMMENTS