Tools & Calculators

Eight questions about your yard's conditions. Returns the approaches that fit, what to check next, what to ask a contractor — and a link into the right calculator for each.

Turn a backyard perc test into inches per hour and minutes per inch, see which fixes your soil rules in or out, and send the rate into the dry well and rain garden tools.

Turn a string-line measurement into a grade, find out whether you have enough fall to drain, and see the drop you need for a pipe or swale.

How much water your roof sheds in a storm and how much lands at each downspout, with NOAA storm depths for your zip code.

Average rainfall by month for any US zip (NOAA 1991–2020) beside its 1- to 100-year one-day storms, what they mean for drainage, and one-click hand-offs into every calculator below.

What size gutters and how many downspouts your roof needs, from your zip code's NOAA rainfall intensity, roof area, pitch and gutter length — with the SMACNA and plumbing-code working shown.

Design flow from the roof, paving and lawn the drain intercepts, checked against the real capacity of 4-inch and 6-inch pipe at your slope.

A yard French drain as a shopping list: stone in yards and tons, pipe, fabric, spoil to haul, turf to cap it, a materials cost range — and whether the run can reach an outlet.

Size a dry well from the water it must hold — pit dimensions, tons of #57 stone, the smaller open-chamber option, and an honest check on whether your soil will drain it.

Size a rain garden from the roof, paving and lawn feeding it: area, footprint, dig depth, soil mix and mulch — and whether the soil empties it in 24 to 48 hours.

How much rain your roof can collect each month from your zip's NOAA averages, how much a barrel or tank keeps and how much overflows — with the overflow handed to the dry well and rain garden tools, and your state's collection rules.

Basin, grate and outlet pipe size from the lawn, paving and roof draining to a low spot, how many basins you need, a shopping list and DIY vs installed ranges.

Blocks, caps, base and drainage stone in tons, fabric, pipe and geogrid — with DIY and installed planning costs and the drainage line item priced.

Cubic yards, tons and bags of topsoil, fill dirt or compost for any shape, with a settling allowance and a bags-vs-bulk break-even — plus a regrading mode that works out the fill wedge for 6 inches of fall away from the house without burying the siding.

Cubic yards, tons and bags of #57 stone, pea gravel, river rock, crusher run or decomposed granite for an area or a trench, in one layer or a base plus a top course — with use presets for driveways, patios, paths, dry creek beds and downspout drainage, each with its sourced depth.

Cubic yards and 2 or 3 cu ft bags of mulch for one bed or several, with extension-recommended depths by mulch type — and how to mulch beside the house and in rain gardens without trapping water at the foundation.

Build your drainage plan line by line — French drain, basins, buried downspouts, dry well, regrading — and get a planning range for the whole job, DIY or installed.

Paste or upload a drainage quote and see how clearly it's documented — what it specifies, what it leaves vague, and the questions to ask before you sign.

Write one clear message to send several drainage contractors so their quotes come back comparable, plus a checklist to vet each one. You send it yourself.