Rain And Your Septic System

Rain and Your Septic System: Everything You Need to Know

Now that it’s officially monsoon season, it’s important to know what happens to your septic system when there’s heavy rain. Excess water, after all, can make it difficult for your system to do its job. It can also cause long-term problems and damage, especially if your system hasn’t received regular maintenance.

However, by understanding the possible effects of rainy weather, you can prevent problems before they arise.

Let’s look at how Arizona rain affects your septic system.


Generally, most rain-related issues involve the drainfield, which is directly exposed to the elements.

But when it comes to monsoon season, it’s best to know how heavy rain can potentially impact your entire system.

Here are three ways excessive rain can cause problems.

  1. Excess Water Flow

Your septic tank is designed to accommodate a certain amount of wastewater from your home.

But if rainwater merges with your wastewater, your septic tank will receive more liquid than it can handle. In turn, your tank will quickly fill up, causing water to back up into your drains or overwhelm the drainfield.

  1. Clogged Drainfield

Normally, liquid waste exits the tank and flows into the drainfield, where bacteria “digest” organic substances. This process creates purified water, which disperses into the surrounding soil.

Heavy rain poses a problem because rainwater can collect on the drainfield. If this happens, the drainfield can’t properly absorb wastewater because it’s already saturated.

Since the water won’t have anywhere to go, it can back up and overflow your septic tank. Eventually, the overflow can move into your plumbing and cause slow drains, gurgling pipes, and stinky odors.

  1. Groundwater Contamination

Excessive rain can also make it difficult for the drainfield to properly purify water.

If the drainfield is already saturated, the liquid waste won’t be able to filter through the soil. Instead, the untreated water will leak out of the pipes before it’s purified.

This wastewater can then accumulate around the drainfield and flow into groundwater, potentially contaminating nearby streams and water sources.


As you can see, heavy rainfall can cause serious septic issues.

There is good news, though. It’s possible to reduce your risk of potential problems before the rain begins.

Here’s how:

  • Prioritize proper septic maintenance. This includes regular septic pumpings and inspections to catch issues early. When your septic system is in good shape, it will be prepared to handle excessive rainfall.
  • Be mindful of what you flush. Avoid flushing feminine hygiene products, diapers, and paper towels. Your septic system can only break down toilet paper and human waste.
  • Pay attention to what goes down the drain. Similarly, don’t put fat, grease, oil, or chemicals in the drains. This includes bleach, gasoline, and paint thinners.
  • Conserve water. While it’s always wise to save water, it’s even more important during rainy weather. Give your system a break by limiting laundry, long showers, and baths when it’s raining.
  • Redirect runoff water. Make sure runoff isn’t combining with your wastewater. Keep gutters away from your drainfield, too.
  • Keep vehicles away from the drainfield. Avoid driving or parking cars, tractors, or motorcycles on the drainfield. Heavy equipment and vehicles can decrease the area’s absorption by compacting the soil.


Understandably, Arizona’s monsoon season can be stressful for homeowners. You might also be concerned about rain and your septic system, especially if you’ve had problems in the past.

Paradise Valley Septic is here to help. Our team of experienced technicians can lend a hand before, during, and after monsoon season. Plus, since we’re familiar with Arizona’s rainy weather, we can provide tips for helping your system stay safe during a monsoon.

To schedule an appointment, contact us at (480) 607-7763 or send us a message online.


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