SWRainAlertSWPPP inspectors
Stop watching the sky and refreshing a weather app between site visits. The rolling 24-hour total, the permit threshold, and the clock are all in one screen — with the form already open to the storm that triggered it.
Built for SWPPP inspectors & general contractors
The storm crossed your threshold. Who's telling your inspector?
SWRainAlert watches NOAA rainfall over every site on your permit and tells the person who has to act — inspector, super, or compliance manager — the moment a storm crosses the trigger, with the deadline already counted in the site's own local time.
No credit card. Continental US coverage · Permit thresholds verified in GA, TX, FL, NC and TN · Forecast warnings from the National Weather Service.
Peachtree Corners — Phase 2
NOAA Stage IV
0.00in
NOAA MRMS
0.00in
Rolling 24 h accumulationThreshold 0.50″
Sources disagree by 0.15″. Both are on the record; the alert used the higher.
On Stage IV alone this storm never crossed 0.50″. Running one source, nobody gets told to inspect.
Monitoring — GA threshold 0.50″ / 24 h
——:——
Two NOAA sources, never averaged
Evaluated every 5 minutes
Forecast warning before the storm
Deadlines in site local time
Signed PDF records
Built for the people who answer for the storm
One rain event. Three different jobs on the line.
The inspector has to be there within the window. The super has to know before the regulator does. The compliance manager has to prove all of it happened, months later, across every site on the permit. SWRainAlert gives each of them the same storm, in the view their job actually needs.
General contractors & site supers
You are the one the fine gets addressed to. Get the same alert your inspector gets, across every site your crews are running, so a missed inspection is never the first you hear of a storm.
Environmental compliance managers
Run the portfolio, not one site at a time. See every open item ranked by how overdue it is, and export a signed, unalterable record when an auditor — or a regulator — asks for one.
Why this exists
Your inspector isn't slow. The tools are.
Federal stormwater penalties run to five figures per day, per violation, and the storm that causes one is rarely the one anyone was watching. It's the second storm that afternoon, or the one that landed while the super was driving between jobs and the inspector was on a different site entirely.
$10,000+a day
Where federal stormwater penalties start — per day, per violation.
5min
How often every site is re-evaluated against its permit threshold.
2sources
Independent NOAA precipitation products, stored side by side, never averaged.
6dry hours
Closes the event so the second storm of the day starts from zero.
The second storm of the day
Most tools accumulate against a calendar day. Two separate storms look like one, the second one never re-triggers, and nobody inspects. We close a rain event after six dry hours so the next storm starts from zero.
The wrong calendar day
A Georgia site evaluated in UTC lands four to five hours off. Inside a 24-hour window that moves the deadline to the wrong day. Every deadline here is computed in the site's own timezone, and a site without one is refused at creation.
Missing data read as dry
Radar gaps carry sentinel values. Treated carelessly they become 0.0 — and a site the radar could not see looks exactly like a site where it did not rain. We render those as unavailable, never as zero.
Differentiator 01
Two independent NOAA sources. We show you both.
Everyone in this market says "synced with NOAA." Nobody runs two independent products side by side and shows you the readings when they disagree.
- NOAA Stage IV — the multi-sensor analysis quality-controlled by the River Forecast Centers. Slower, and the defensible record.
- NOAA MRMS — NSSL radar with automated gauge bias correction, near real time. This is what gets you moving.
- Never averaged. An average invents a number neither source reported and makes the audit trail unexplainable.
- Alerts on the higher reading, and flags the divergence on the dashboard and on the inspection report.
The rain event, start to finish
One event. One notification per transition.
The evaluator runs every five minutes. Notification decisions ride on the event's own flags — never on "did the number change since the last poll" — so a storm sends one alert, not twelve.
The rule that matters most
Rolling 24 hours, and a hard reset after six dry hours.
Accumulation is measured on a rolling window, not against midnight. A storm that starts at 22:00 and runs to 02:00 is one storm, and it is measured as one.
Then the event closes. Six hours with no accumulation ends it, the inspection clock for that event stops, and the next storm builds its own total, sends its own alert and gets its own deadline.
Honest about the edge: a storm that clears the threshold in a single reading never passes through APPROACHING. It goes straight to BREACHED, and the alert goes out on that transition.
Differentiator 02
Reasoning about the permit. Photos help; they never decide.
Our ground is the rules: which requirements this storm triggered under this permit, what deadlines follow, and which corrective-action clocks are now running. Where we look at a photograph, it drafts a finding for a person to accept — it never files one, and it never decides whether a site is compliant.
- State inspection forms for Georgia, North Carolina and South Carolina, prefilled with the storm total and its source — never with a gauge reading we do not have.
- Photo and video evidence, captured on the phone and attached to the inspection, including offline at the site — with an optional drafted finding you edit and accept, or discard.
- Corrective actions tracked with their own clock, and a weekly opened-versus-closed trend so you can see whether the backlog is growing.
- Signed PDF records rendered from the form snapshot as filed — a record that changes after it was signed is worthless.
Differentiator 03
An alert after the rain is useful. A warning before it is worth more.
Observed rainfall tells you an inspection is now due. A forecast tells you to stabilise the slope, empty the basin or move the crew while there is still time to do any of it.
- An advisory at 24 hours. When the National Weather Service forecast for a site reaches that site’s own permit trigger inside a day, the people who cover it hear about it — once per episode, not every hour the forecast repeats.
- Rain-relevant NWS alerts for each site’s own grid cell, so a flash flood warning over your site is not something you catch on the radio.
- Scored against what actually fell. Every forecast is kept and later compared with the observed reading — hits, misses, false alarms and average error, per site and fleet-wide. You can see how much the warning is worth before you act on it.
A forecast creates no obligation. Your permit triggers on rain that fell. The inspection clock starts on an observed reading, never on a prediction, and we keep the two in separate records so a forecast that missed can never look like a storm that happened.
See it before you sign up
The app your inspector will actually use.
Eight real screens from the Android client, not mockups drawn to sell you something. It plays itself below — or tap any label and step through it yourself.
Coverage
Every state's permit is different. We read them, and we say which ones we checked.
The threshold that triggers your inspection is set by your state's construction general permit, and permits expire. Reading two permit eras as concurrent rules is the standard way this gets wrong — it is how a "dual trigger" that never existed ends up in a product.
So every threshold we ship is checked against the primary permit text, with its effective and expiry dates, and the ones we have not fully confirmed are labelled as such rather than presented as fact.
Trigger
0.50″
Window
24 h
Respond within
24 h
VerifiedGAR100001, effective 2023-08-01, expires 2028-07-31. Checked against the primary permit text.
Shipped defaults, not legal advice. Your permit or a Sensitive Waters designation can be stricter; every threshold is editable per site.
How we differ
What to ask before you put your name on a vendor contract
You're the one who has to defend this system to an auditor. Five questions worth asking any rainfall alerting vendor before you sign — including us.
| The question | Typical answer | SWRainAlert |
|---|---|---|
| How many rainfall sources? | One, described as "NOAA data" | Two independent NOAA products, both stored, alert on the higher ✓ |
| What do you show me when sources disagree? | Nothing — there is only one number | Both readings and the divergence, on screen and on the report ✓ |
| What happens on the second storm of the day? | Often nothing; accumulation runs to midnight | Six dry hours close the event; storm two alerts on its own ✓ |
| What do you do when the radar can't see my site? | Reports 0.00″ | Reports unavailable. A gap is never rendered as dry ✓ |
| Where did your state threshold come from? | Unstated | Named permit, with effective and expiry dates, and a verification status ✓ |
"Typical answer" describes patterns we have observed in publicly available marketing and documentation across this category. Ask your current vendor directly — the answers are the point, not our summary of them.
Questions
Straight answers
Does this replace my on-site rain gauge?
No. Where your permit names an on-site gauge as the system of record, the gauge is the record. SWRainAlert is a monitoring and recordkeeping aid: it tells you when to go look, and keeps a defensible trail of what NOAA reported. We say this in the app, not buried in terms — inspectors know the rules better than we do.
Which rainfall data do you use?
Two independent NOAA products. Stage IV is the multi-sensor analysis quality-controlled by the River Forecast Centers — slower to arrive, and the defensible record. MRMS is NSSL's radar analysis with automated gauge bias correction, near real time. Both are stored per site, per source. We alert on the higher and flag any divergence.
What happens when a second storm hits the same day?
After six hours with no accumulation the rain event closes. The next storm accumulates from zero and gets its own alert, its own threshold evaluation and its own inspection deadline.
How often do you check, and how many alerts will I get?
The evaluator runs every five minutes. You get one notification per event per transition — a storm that breaches once sends one breach alert, no matter how many times it is re-evaluated while it rains.
Which states are supported?
Rainfall alerting covers the continental United States. Permit thresholds and inspection forms are curated state by state: Georgia, Texas, Florida, North Carolina and Tennessee are verified against the current construction general permit; South Carolina and Alabama are marked partial, with the reason given. Uncurated states fall back to the federal 0.25″ baseline.
What happens if I go over my site limit?
You are blocked from creating new sites until you upgrade. You are never blocked from reading your data, receiving alerts, editing a threshold or retrieving a filed inspection. A billing state should never cost someone access to their own compliance record.
Does SWRainAlert warn me before a storm, or only after?
Both. The inspection trigger is observed rainfall from two NOAA products, because that is what your permit is written against. Separately, we read the National Weather Service forecast for each site and send an advance advisory when the forecast reaches that site’s trigger within 24 hours, plus any active rain-relevant NWS alerts. The forecast creates no obligation — it buys you time to prepare.
Can I get this data into our own systems?
Yes. Scoped API keys give read-only or read-write access, and outbound webhooks push breach, forecast advisory, weather alert and inspection events to your endpoint, signed with HMAC so you can verify they came from us. The API documentation covers both, and the sandbox lets you try the rainfall logic before you have an account.
Does it work without a signal on site?
Yes. The mobile app paints your cached fleet before it tries the network, queues inspections and photos in a write outbox, and always tells you how old the cached data is.
The next storm is coming. Decide now who finds out first.
Thirty days of the Complete plan, every feature, no card. Add your sites by address or by dropping a pin, and the inspector, the super and the compliance file are all covered before the first drop lands.