RoofRainYield

Gallup, NM rainwater: 11,167 gallons off a roof

How much rain a roof in Gallup, NM collects

11,167gallons a year

That is a 1,500 sq ft asphalt roof under Gallup, NM's normal 14.1 inches of rain, about 795 gallons for every inch that falls.

Gallup, NM has gaps between storms long enough to drain a single barrel. Around 275 gallons of storage catches most of what is worth catching.

Rainfall: NOAA 1991-2020 climate normals, the Gallup 1.0 Sse station (0.9 mi away). Gallup, NM ranks 6th wettest of the 19 cities covered in New Mexico.

Month by month in Gallup

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.281,017
Feb1.24986
Mar1.09866
Apr0.74588450
May0.87691434
Jun0.38302495
Jul1.791,423319
Aug2.431,931239
Sep1.491,184357
Oct1.01803416
Nov0.70556
Dec1.03819

Aug is the wettest month (2.43 in, 1,931 gal off the roof); Jun the driest (0.38 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

Barrel or cistern in Gallup?

Best fit: a 275-gallon tote or tank, which delivers about 2,388 gallons to the garden in a normal year (88.1% of its need).

If you set one up, link barrels with a short hose at the base so they fill and drain together, and check the overflow points away from the house.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal1,1849,458
110 gal1,7568,886
165 gal2,0538,589
275 gal2,3888,254
550 gal2,4588,184
1,000 gal2,4588,184
1,500 gal2,4588,184
2,500 gal2,4588,184
5,000 gal2,4588,184

Simulated storm by storm through a normal year using the station's count of days with 0.1 in or more of rain each month.

Is rainwater collection legal in New Mexico?

Regulated through the State Engineer Office; no specific requirements exist for outdoor uses; indoor uses must meet quality standards; check county for local incentives

From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source