How to Monitor Your Google Sheet Automatically (No Code Required)

Google Sheets is great for tracking stuff. But it has one huge flaw: it only works when you're looking at it. It won't tap you on the shoulder and say "hey, something changed" or "hey, this payment is missing."

I spent 3 years trying to solve this. Here's every approach I tried, from DIY to purpose-built, and what actually worked.

Option 1: Google Sheets Built-in Notification Rules

Google Sheets has a little-known feature called notification rules. Go to Tools > Notification rules. You can set it to email you when "any changes are made" or "a user submits a form."

Sounds perfect, right? It's not.

What it does: Sends you an email when someone edits the sheet. You can choose instant or daily digest.

What it doesn't do: Anything smart. It can't tell you "Unit 4A hasn't paid." It just says "someone edited cell F7." No context. No logic. No filtering.

If you share your sheet with tenants or a property manager and they make edits, you'll get flooded with useless notifications. And if nobody edits the sheet, you get nothing. Which is exactly the problem. No payment showing up means no edit means no notification.

Verdict: Almost useless for rent monitoring. It tells you when something changes, not when something is missing. And missing payments are exactly what you need to catch.

Option 2: Google Apps Script

Apps Script is Google's built-in scripting language. You can write JavaScript that reads your sheet, checks for conditions, and sends emails.

Here's roughly what the code looks like:

function checkOverdueRent() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('January');
  var data = sheet.getDataRange().getValues();
  var today = new Date();

  for (var i = 1; i < data.length; i++) {
    var dueDate = new Date(data[i][3]); // Column D
    var datePaid = data[i][5]; // Column F

    if (!datePaid && today > dueDate) {
      MailApp.sendEmail('[email protected]',
        'Overdue: ' + data[i][0],
        data[i][1] + ' has not paid for ' + data[i][0]);
    }
  }
}

Then you set a daily trigger to run it automatically.

Pros: It's free. It's flexible. You can customize the logic however you want.

Cons: You need to write code. You need to maintain it. Google changes things and your trigger breaks silently. I ran an Apps Script for 6 months. It broke twice and I didn't realize either time for over a week.

The silent failure is the killer. When your monitoring system breaks and doesn't tell you it broke, you're right back to the original problem. You think you're covered, but you're not.

Verdict: Works if you're a developer. Risky if you're not. Silent failures make it unreliable for something as important as rent collection.

Option 3: Zapier + Google Sheets

Zapier connects different apps together. You can create a "Zap" that triggers when your Google Sheet is updated and sends you a Slack message, email, or text.

The setup looks like: Trigger = "New or Updated Spreadsheet Row in Google Sheets." Filter = "Date Paid is blank AND Due Date is before today." Action = "Send Email" or "Send SMS via Twilio."

Pros: No code required (technically). Visual workflow builder. Lots of integrations.

Cons: It's expensive. Zapier's free tier gives you 100 tasks/month. Running a daily check on 12 units is 365 tasks/month. That's $20+/month on Zapier's Starter plan. And that doesn't include SMS costs if you're routing through Twilio.

The bigger issue is complexity. To check for missing payments (not just new payments), you need multi-step Zaps with filters and conditional logic. It took me over 2 hours to set up. And when my sheet layout changed slightly, the Zap broke.

Also, Zapier triggers on changes. If a cell is already blank (meaning rent was never paid), there's no "change" to trigger on. You have to get creative with scheduled Zaps, which adds more complexity and cost.

Verdict: Possible but painful. Overkill for what should be a simple problem. And surprisingly expensive once you factor in all the pieces.

Option 4: Purpose-Built Monitoring Tools

This is where tools built specifically for spreadsheet monitoring come in. Instead of stitching together generic tools, you use something designed from the ground up to watch a sheet and alert you.

The difference is intent. Generic tools (Zapier, Apps Script) can do anything, which means you have to configure everything. Purpose-built tools know what to look for.

For landlords specifically, this means a tool that understands rent rolls. It knows what a due date column looks like. It knows what a blank "Date Paid" cell means. It knows about grace periods.

You don't have to write code. You don't have to build Zaps. You just connect your sheet and tell it which columns are which.

RentGuard: The Landlord-Specific Option

I built RentGuard after going through all three options above and being frustrated by each one.

Here's how it works:

Step 1: Connect your Google Sheet. Takes about 2 minutes. You grant read access and tell it which sheet to monitor.

Step 2: Map your columns. Tell RentGuard which column is the unit number, which is the rent amount, which is the due date, and which is the date paid. Takes another 2 minutes.

Step 3: Set your grace period. Mine is 5 days. Some landlords use 3. Some use 0. Up to you.

That's it. From then on, RentGuard checks your sheet daily. If rent is overdue past the grace period and the Date Paid column is blank, you get a text message and an email. On day 1. Not day 11.

Your spreadsheet doesn't change at all. Same layout, same formulas, same data. RentGuard just reads it and alerts you.

Comparison at a Glance

Notification rules: Free. No code. But can't detect missing data. Basically useless for rent monitoring.

Apps Script: Free. Requires code. Breaks silently. Great if you're a developer who checks their triggers regularly.

Zapier: $20+/month. No code (sort of). Complex setup. Triggers on changes, not missing data. Fragile.

RentGuard: $15/month. No code. 5-minute setup. Purpose-built for rent rolls. Text + email alerts. Detects missing payments, not just changes.

The right choice depends on your comfort level. If you can write and maintain JavaScript, Apps Script is free and flexible. If you want something that just works and you never have to think about, a purpose-built tool saves you the headaches.

For a deeper look at setting up Sheets alerts, check out my post on Google Sheets late rent notifications. For change-based notifications specifically, see how to get notified when your Google Sheet updates. And for more ways to automate your landlord spreadsheet, read how to automate your landlord spreadsheet.