RoofRainYield

Hobbs, NM rainwater: 10,944 gallons off a roof

Hobbs, NM: gallons off the roof each year

10,944gallons a year

That is a 1,500 sq ft asphalt roof under Hobbs, NM's normal 13.8 inches of rain, about 795 gallons for every inch that falls.

Hobbs, NM has gaps between storms long enough to drain a single barrel. Around 165 gallons of storage catches most of what is worth catching.

Rainfall: NOAA 1991-2020 climate normals, the Hobbs station (1.7 mi away). Hobbs, NM ranks 7th wettest of the 19 cities covered in New Mexico.

Month by month in Hobbs

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan0.50397
Feb0.53421
Mar0.63501
Apr0.76604448
May1.911,518304
Jun1.271,009384
Jul1.741,383325
Aug2.061,637286
Sep2.461,955236
Oct0.87691434
Nov0.53421
Dec0.51405

Sep is the wettest month (2.46 in, 1,955 gal off the roof); Jan the driest (0.50 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

Which tank size is worth it in Hobbs

Best fit: 3 linked 55-gallon barrels, which delivers about 2,016 gallons to the garden in a normal year (83.4% 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 gal9909,624
110 gal1,7628,853
165 gal2,0168,598
275 gal2,2308,384
550 gal2,2338,382
1,000 gal2,2338,382
1,500 gal2,2338,382
2,500 gal2,2338,382
5,000 gal2,2338,382

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