Las Cruces Yard Guide
Rainwater Harvesting in Las Cruces
Las Cruces gets only about 8 to 9 inches of rain a year, and more than half of it falls in a few monsoon months. That makes every storm worth catching. A roof, a gutter and a low spot in the yard can water trees for weeks. Here’s what’s legal, how much you can collect, and which setup fits your yard.
Updated September 2026 using New Mexico Office of the State Engineer guidance.
Quick answer
Is rainwater harvesting legal in Las Cruces?
Yes. The New Mexico Office of the State Engineer says most homeowners can install and use a rainwater harvesting system for landscape irrigation without public health or water rights concerns. Rooftop rain barrels, cisterns and rain basins that water your own yard are all common in Las Cruces.
Using rainwater indoors or for drinking is a different matter. It needs treatment and plumbing that meets code, so this guide sticks to watering landscapes.
Three ways to harvest rain
|
Method |
Best for |
|---|---|
|
Rain basins and swales |
Trees and shrubs, lowest cost |
|
Rain barrels |
Small beds and pots |
|
Cisterns |
Storing monsoon rain for dry months |
|
Mulch and berms |
Holding water at each plant |
The math
How much rain can my roof collect?
Each inch of rain on each square foot of roof yields about 0.62 gallons. A 1,500 sq ft roof collects about 930 gallons from a one-inch storm and up to about 7,900 gallons in an average year, before losses from splash, evaporation and overflow.
|
Roof area |
Per 1 inch of rain |
Per year (about 8.5 in) |
|---|---|---|
|
1,000 sq ft |
About 620 gal |
About 5,300 gal |
|
1,500 sq ft |
About 930 gal |
About 7,900 gal |
|
2,000 sq ft |
About 1,240 gal |
About 10,500 gal |
|
2,500 sq ft |
About 1,550 gal |
About 13,200 gal |
Measure only the roof area that drains to the gutter or canale you’re collecting from. Real yields run lower than these totals.
Choose a system
Rain barrels, cisterns or rain basins: which is best?
For most Las Cruces yards, rain basins give the most value, because the soil stores the water for free. Barrels are cheap but fill fast: one 55-gallon barrel fills from less than a tenth of an inch on a 1,500 sq ft roof. Cisterns carry monsoon rain into fall.
Rain basins
Shallow, rock-lined depressions around trees that catch roof and yard runoff. No tank, no pump.
Rain barrels
50 to 100 gallon barrels at downspouts or canales. Good for pots and small beds.
Cisterns
Larger tanks with a level pad, overflow and often a pump to feed drip lines.
Set it up
How do I set up a rainwater system safely?
Clean the gutters, screen the inlet, add a first-flush diverter to shed the dirtiest water, set tanks level on a solid base, and send the overflow away from the house to a basin. Keep every opening sealed so mosquitoes can’t breed, and use the water on landscapes only.
1
Pick the downspout
Choose the one draining the most roof area near thirsty plants.
2
Screen and divert
A leaf screen and first-flush diverter keep debris out of the tank.
3
Level base
A full 55-gallon barrel weighs about 460 lb; set it on a firm, level pad.
4
Plan the overflow
Pipe overflow at least several feet from the foundation into a basin.
5
Seal it
Tight lids and fine screens keep mosquitoes and kids out.
6
Use it
Empty barrels between storms so they’re ready for the next one.
Timing
When does Las Cruces get most of its rain?
More than half of the yearly rain usually falls in July, August and September during monsoon season. Winter storms are smaller and less frequent. Plan storage and basins to capture monsoon downpours, then use stored water in the dry fall and spring months.
Before monsoon
Clean gutters, check screens, and dig or refresh basins in June.
During storms
Watch where water runs. Move overflow away from walls and walkways.
Dry months
Use stored water on trees and shrubs, then top up with drip on your watering days.
Cost
How much does rainwater harvesting cost?
Rain basins cost the least, often just grading and rock around existing trees. A rain barrel setup usually runs a few hundred dollars with the diverter and base. Cisterns cost more with tank size, pad, pump and piping. Downspout drains run about $150 to $350 each.
Moving water across the yard? See drainage solutions.
Related guides and services
Free tool
Rainwater harvest calculator
See how many gallons your roof can collect from each storm and in an average Las Cruces year.
Your result
Gallons per storm and per year will show here.
Rainwater harvesting FAQs
Want to catch more monsoon rain?
We design rain basins, dry creek beds and downspout routing that water your trees and keep runoff away from the house. Free, written estimate.
Las Cruces Landscaping Group
1921 Santa Ines Drive, Las Cruces, NM 88011
(575) 270-0676. Mon to Sat, 7 a.m. to 7 p.m.
Request a Free Estimate
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