How much water should a soaker hose apply?
A soaker hose is a length of porous tubing that weeps water along its entire surface, rather than through individual holes or emitters. Because it wets a whole strip of soil at once, it belongs in the wider family of drip and micro-irrigation tools, which the EPA's WaterSense program credits with typically using 20 to 50 percent less water than a conventional pop-up sprinkler system, since the water goes straight to the root zone instead of being lost to wind, overspray and evaporation.
Colorado State University (CSU) Extension gives a useful rule of thumb for vegetable gardens: plants use roughly ¼ inch of water a day in typical summer weather, so if you water every four days, aim for about 1 inch per irrigation. Hot, windy weather, and crops in bloom or setting fruit, raise that demand; cooler weather and young seedlings need less.
| Conditions | Typical target | Notes |
|---|---|---|
| Typical summer weather, watering every 4 days | about 1 in (25 mm) | CSU Extension's rule of thumb of roughly ¼ in/day. |
| Hot, windy spells; crops blooming or setting fruit | toward the upper end, more often | Beans and corn draw noticeably more water while flowering or tasseling. |
| Seedlings and recent transplants | smaller amounts, more often | Shallow young roots dry out faster between sessions. |
| Cool spring or fall weather | less than the summer target | Growth and evaporation both slow down. |
Once you have a depth or a volume in mind, this calculator turns it into a run time for your specific hose. If you'd rather work from a soil-moisture check than a fixed schedule, CSU Extension suggests digging down two to four inches and watering once that layer feels dry, then using the calculator to time the session.
Check local rules first. Many water utilities set watering days, hours or weekly limits. Where those apply, they take priority over any calculated target.
How this soaker hose calculator works
The calculator multiplies your hose's output rate by its length to get a total flow rate, works out the volume of water your target represents, then divides one by the other to get a run time.
1. Total flow rate from your hose
Total flow rate
Total flow rate = Output rate per foot × Hose length
Output per foot and the hose's rated maximum length come from the manufacturer, or from your own measurement. Treat any number you didn't measure or read off the packaging as typical, not exact.
2. The water your target represents
If you enter a depth over a bed area, the calculator converts that to a volume. If you already know the volume you want to apply, it skips straight to step 3.
US units
Gallons = Bed area (sq ft) × Depth (in) × 0.623
One inch of water over one square foot is 144 cubic inches, and a US gallon is 231 cubic inches. 144 ÷ 231 ≈ 0.623.
Metric units
Liters = Bed area (m²) × Depth (mm)
One millimeter of water over one square meter is exactly one liter.
3. Run time
Run time
Minutes = Target volume ÷ Total flow rate × 60
Useful conversions
| Water depth | Over this area | Volume |
|---|---|---|
| 1 in | 1 sq ft | 0.623 gal |
| 1 in | 32 sq ft | 19.9 gal |
| 1 mm | 1 m² | 1 L |
| 15 mm | 1 m² | 15 L |
| 1 in = 25.4 mm | 1 US gal = 3.785 L | |
For a plain depth-to-volume conversion without the hose math, use the inches of water to gallons calculator. Run time is shown as "about," since it depends on an output rate that is itself an estimate unless you measured it directly.
When this calculator isn't the right tool
It's built for a soaker hose that seeps water along its whole length. Use a different tool for:
- Point-source drip tubing or emitters, where individual drippers, not the whole line, release water at fixed spots. See the drip run time calculator or the drip emitter calculator.
- Whole-lawn watering, where sprinklers cover an open area instead of a planted bed. See the lawn watering calculator.
- Sizing a pressure regulator for your drip or soaker setup. See the drip pressure regulator calculator.
- Long agricultural rows using drip tape, which has its own emitter spacing and flow characteristics. See the drip tape calculator.
Soaker hose run time example
A 4 ft by 8 ft raised bed (32 sq ft) is watered with a 25-foot soaker hose. A bucket test measured its output at 0.6 gallons per hour per foot, and the goal is 1 inch this session.
- Total flow rate: 0.6 gal/hr per ft × 25 ft = 15 gal/hr.
- Target volume: 32 sq ft × 1 in × 0.623 ≈ 19.9 gal, shown as about 20 gallons.
- Run time: 19.9 gal ÷ 15 gal/hr × 60 ≈ 79.8 min, shown as about 1 hr 20 min.
The same calculation in metric
A 3 m by 1.5 m bed (4.5 m²) is watered with an 8-meter soaker hose rated at 5 liters per hour per meter, aiming for a 15 mm depth:
- Total flow rate: 5 L/hr per m × 8 m = 40 L/hr.
- Target volume: 4.5 m² × 15 mm = 67.5 L, shown as about 70 liters.
- Run time: 67.5 L ÷ 40 L/hr × 60 ≈ 101.3 min, shown as about 1 hr 41 min.
Notice that the run time in both examples is longer than a typical sprinkler session. That's expected: a soaker hose trades a fast application rate for gentler, more even coverage with less runoff.
Getting even watering from a soaker hose
Seattle Public Utilities' consumer guidance on soaker hoses, widely reproduced by other water utilities, covers the setup details that most affect how evenly a soaker hose actually waters:
- Start at the faucet. Connect a backflow preventer first, unless your faucet already has one built in, then add a pressure regulator set to 10 or 12 psi before attaching the hose.
- Slow the flow. Turn the faucet on just enough that the entire hose is seeping, not spraying. The right amount varies by faucet, so start with a small adjustment and watch the hose.
- Keep runs short. Seattle Public Utilities puts the maximum effective length at 100 feet, the longest length most soaker hoses are sold in. CSU Extension is more conservative, recommending about 25 feet or less so the far end of the line doesn't run noticeably drier than the end near the faucet. For a longer bed, connect several shorter runs on separate zones instead of one long line.
- Keep it level. Soaker hoses deliver water most uniformly on level ground; on a slope, use shorter lengths so pressure doesn't pool water at the downhill end.
- Space the lines. Seattle Public Utilities recommends 12 to 18 inches apart in sandy soil and 18 to 24 inches apart in loam or clay soil, keeping the hose 1 to 2 inches from the base of established plants. For raised beds, CSU Extension suggests a simpler 12-inch spacing, running the line up and down the box; a 4-foot-wide box typically takes four runs.
- Time it, then adjust. Start with about 30 minutes twice a week, check how far the moisture has penetrated afterward, and adjust the run time from there. Once you know the number that works, this calculator can convert a new hose length or target back into minutes without re-testing from scratch.
- Maintain the hose. Flush the line by opening the end cap and running water through it when you first install it and a few times each season, and cover it with 2 to 3 inches of mulch to protect it from UV breakdown and help hold moisture in.
For plant-by-plant coverage in a small bed, the raised bed watering calculator and the drip wetted area calculator go further into layout and coverage.
Factors that change soaker hose run time
The output rate you enter is the biggest lever in the calculation, and several things can shift it from what the packaging says.
| Factor | Effect on output | What to adjust |
|---|---|---|
| Hose length | Longer runs lose pressure toward the far end, so output isn't uniform along the whole line. | Keep runs to about 25 ft (CSU Extension) to 100 ft (Seattle Public Utilities) and split longer beds into zones. |
| Spigot pressure | Too much pressure causes spraying or bursting; too little gives a weak, uneven seep. | Add a hose-end pressure regulator rated around 10–12 psi. |
| Hose diameter and construction | Wider hoses and different pore materials pass different amounts of water at the same pressure. | Use the manufacturer's rated output for your specific hose, not a generic figure. |
| Slope | Water tends to seep out faster near the top of a slope and pool at the bottom. | Run shorter lengths across slopes, or split into zones that follow the contour. |
| Soil type | Sandy soil drains fast and holds less water; clay absorbs slowly but holds more. | Sandy: smaller, more frequent sessions. Clay: fewer, longer sessions with time to soak in. |
| Debris and mineral buildup | Sediment and hard-water deposits can clog the pores over a season, reducing flow. | Flush the hose periodically and re-measure its output if flow seems to drop. |
Because several of these change gradually over a season, a bucket-test measurement from a year ago may no longer match your hose's real output today. Re-testing before a long dry spell is worth the few minutes it takes.
Frequently asked questions
How long should I run a soaker hose?
It depends on your hose's output rate, its length, and how much water you're aiming to apply. Multiply the output rate per foot by the hose length to get the total flow rate, then divide the volume of water you want to apply by that flow rate. As a rough cross-check, CSU Extension notes that a soaker hose run through a proper hose-end pressure regulator often needs about 10 to 20 minutes to adequately water a garden, while the same hose using only its built-in flow disc may need close to an hour.
How do I find my soaker hose's output rate?
Check the hose's packaging or the manufacturer's spec sheet first, since output is usually given in gallons per hour, or liters per hour, at a stated length and pressure. If that isn't available, run the whole hose into a large container for a timed interval, such as 10 minutes, measure the gallons collected, then divide by the time in hours and again by the hose's length to get an output rate per foot.
How long can a soaker hose be?
Guidance varies by source. CSU Extension recommends keeping soaker hose runs to about 25 feet or less, since longer lines deliver more water near the supply end and less at the far end. Seattle Public Utilities puts the maximum effective length at 100 feet, which is also the longest length most soaker hoses are sold in. For a bed longer than that, use several shorter runs on separate zones rather than one long line.
What water pressure does a soaker hose need?
Most soaker hoses are designed for low pressure, generally around 10 to 12 psi. Seattle Public Utilities recommends adding a pressure regulator set to that range before attaching the hose, and turning the faucet on only enough that the hose seeps rather than sprays. Household pressure straight from the tap is usually far higher and can split the hose or cause uneven output.
How far apart should soaker hose lines be spaced?
Seattle Public Utilities recommends 12 to 18 inches apart in sandy soil and 18 to 24 inches apart in loam or clay soil, keeping the hose 1 to 2 inches from the base of established plants. CSU Extension suggests a simpler 12-inch spacing for raised beds, with multiple runs across the width of the box.
Is a soaker hose a good choice for a vegetable garden?
Yes. Clemson Cooperative Extension lists drip and trickle irrigation, which includes soaker hoses, as the best method for conserving water in a vegetable garden, and EPA WaterSense notes that drip-type systems typically use 20 to 50 percent less water than a conventional pop-up sprinkler system. Keeping water at the soil surface instead of on the leaves also helps limit foliar diseases.
How is a soaker hose different from drip tubing?
A soaker hose seeps water along its entire porous length, watering a strip evenly rather than at individual points. Drip tubing instead uses separate emitters spaced along solid tubing, with each emitter putting out a fixed rate at its own location.
If you're working with emitter-based drip tubing rather than a soaker hose, the drip run time calculator matches its math to that setup.
Do I need a backflow preventer for a soaker hose?
Seattle Public Utilities recommends connecting a backflow preventer at the faucet before attaching a soaker hose, unless your faucet already has one built in. This keeps garden water, soil and anything drawn back through the hose from siphoning into the drinking water supply. Check your local plumbing code, since some jurisdictions require it.
Who built and checked this calculator
Licensed Professional Engineer and Irrigation Association Certified Irrigation Designer with more than 20 years in irrigation design, system auditing and landscape water management. Full profile
How this page was checked
- Formulas, unit conversions and both worked examples verified by hand.
- Length, spacing and pressure guidance checked against the extension and utility sources below.
- Every "typical" figure is labeled as such; output rate is left blank rather than pre-filled, since it varies by product.
Sources
- Colorado State University Extension. CMG GardenNotes #714: Irrigating the Vegetable Garden.
- Seattle Public Utilities. Soaker Hoses.
- Clemson Cooperative Extension, Home & Garden Information Center. Watering the Vegetable Garden.
- U.S. EPA WaterSense. Water-Saving Technologies.