RoofRainYield

Abbeville, LA rainwater: 51,869 gallons off a roof

Rainwater from a roof in Abbeville, LA

51,869gallons a year

That is a 1,500 sq ft asphalt roof under Abbeville, LA's normal 65.3 inches of rain, about 795 gallons for every inch that falls.

Abbeville, LA gets enough rain in the growing season that a 200 sq ft garden rarely needs topping up, so a tank here is about saving the occasional dry spell, not a summer of watering.

Rainfall: NOAA 1991-2020 climate normals, the Abbeville station (0.8 mi away). Abbeville, LA ranks 10th wettest of the 35 cities covered in Louisiana.

Month by month in Abbeville

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan5.764,578
Feb4.143,290
Mar3.973,155
Apr5.084,038
May4.833,839
Jun7.385,866
Jul7.095,635
Aug7.245,754
Sep5.664,499
Oct5.114,061
Nov4.553,616
Dec4.453,537

Jun is the wettest month (7.38 in, 5,866 gal off the roof); Mar the driest (3.97 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 Abbeville?

Best fit: a 5,000-gallon cistern, which delivers about 0 gallons to the garden in a normal year.

If you buy one, a single 55-gallon barrel is plenty here; spend the money on a first-flush diverter and a screen rather than more storage.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal050,669
110 gal050,669
165 gal050,669
275 gal050,669
550 gal050,669
1,000 gal050,669
1,500 gal050,669
2,500 gal050,669
5,000 gal050,669

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 Louisiana?

No rainwater harvesting regulations

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