RoofRainYield

Webster, TX rainwater: 48,221 gallons off a roof

Rainwater from a roof in Webster, TX

48,221gallons a year

That is a 1,500 sq ft asphalt roof under Webster, TX's normal 60.7 inches of rain, about 795 gallons for every inch that falls.

Webster, TX 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 Webster 0.4 Nw station (0.5 mi away). Webster, TX ranks 9th wettest of the 252 cities covered in Texas.

Month by month in Webster

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan4.603,656
Feb3.072,440
Mar3.552,822
Apr5.504,371
May5.444,324
Jun5.654,491
Jul4.913,902
Aug6.515,174
Sep6.385,071
Oct6.104,848
Nov4.583,640
Dec4.383,481

Aug is the wettest month (6.51 in, 5,174 gal off the roof); Feb the driest (3.07 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 Webster?

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

If you set one up, 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 gal047,201
110 gal047,201
165 gal047,201
275 gal047,201
550 gal047,201
1,000 gal047,201
1,500 gal047,201
2,500 gal047,201
5,000 gal047,201

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 Texas?

Rainwater harvesting is legal and encouraged; no state storage cap. HOAs may not adopt new covenants banning rainwater harvesting installations but may require screening. Local taxing units may exempt property with water conservation initiatives from property tax (Tax Code 11.32).

Checked against the current source on 2026-11-06. Source