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Maintaining a Rainwater Harvesting System

Curious what type of maintenance is required for a rainwater harvesting system? For the purposes of this article, we are discussing maintaining potable systems (i.e., rainwater systems that provide households with drinking water). When you live on rainwater, you are essentially maintaining your own utility, and you’ll want to ensure it provides the highest quality of water for you and your family.

Read below as we break down rainwater system maintenance. If you have an irrigation rainwater system, scroll to the bottom for our best nonpotable maintenance tips. 

If you are interested in scheduling a service maintenance appointment with our team, contact us here.


We’re going to start at the beginning of a rainwater catchment system – the roof and gutters and move down the conveyance line to the tank and finally your disinfection station.

2-4x/year (more frequently if you have overhanging trees) 

We always recommend snap-in leaf guards for gutters (not micromesh) when designing a new system or upgrading an older one. These screens act as the first step of pre-filtration for your collected rainwater, keeping most leaf, tree, and animal material (birds, squirrels, nests, etc.) from entering your storage tank.

You’ll want to wipe off these leaf guards and ensure both roof and gutters are free of excess debris. Fine dust particulates, etc., do not need to be entirely removed from the roof as your sediment filter will handle these.

2-4x / year

With all Harvest Rain potable installations, we include a first-flush to reduce the amount of sediment that ends up in your storage tank. Typically, these first flushes are a run of pipe that ends with a screen.

You’ll want to remove this small screen and rinse. We recommend cleaning the first flush screen on the same day(s) you change your filters and checking after significant weather events.

Your system may utilize an eliminator tank instead of a first-flush. If that’s the case, you’ll need to check that the eliminator automatically drains when full or periodically manually drain to ensure flush capacity during the next rain.

TIP: if your rainwater system does not have a first-flush or an eliminator tank, we invite you to schedule a service call to discuss an upgrade.

2-4x / year

All potable rainwater tanks should have a leaf basket/strainer where the inlet pipe meets the tank. There should also be a removable coupling or some way to detach the last PVC fitting/pipe that enters into the tank. Remove this fitting, then the leaf basket, wipe out any debris, rinse with water, and re-install.

Rainwater Tank and Leaf Basket Location

NOTE: Cleaning of the interior of a tank is typically only necessary every 15-20 years to help remove any accumulated sediment. 

When designing a system for a property with many oaks or overhanging trees in general, we first recommend trimming back tree limbs to prevent excess debris on the roof. Other times, we may also recommend a recirculation system to help negate pollen build-up (which can turn your water a light green – not harmful, but unsightly for sure!)

Give us a ring if you think your tank may need cleaning – we’re happy to direct you to some great resources.


The disinfection station is the most essential component of your potable rainwater system. Here, your stored rainwater runs through a sediment filter, a carbon filter, and finally, a UV lamp. If your system does not contain all three steps, we do not consider it a complete disinfection station.

Rainwater Disinfection System
Viqua E4 Ultraviolet Disinfection System

Frequency-based on size + demand 

The sediment filter should be the first in the disinfection line. We use sediment filters rated @ 5 Microns (meaning they remove anything 5 microns or bigger such as sand, silt, rust.)

Depending on the size of your filter housings, usage level, and the number of occupants, we recommend changing sediment filters monthly or quarterly. Smaller filter systems (2.5″X10″) require monthly changes. Larger systems, such as the Viqua E4 picture above, typically only need to be changed quarterly.

Most Common Filter Sizes

Your system may be equipped with two of the same size filter housings (aka sumps) or two different, depending on the installer and date of installation. Sediment and carbon filters come in various sizes, but the three most common are: 2.5 x 10″; 2.5 x 10″, 4.5″ x 20″.

Most Common Filter Housings for Rainwater
Unsure of what size filter your system uses? Contact us – we’re happy to help identify components. 

TIP: If you notice a reduction in water pressure, your sediment filter is the first place to check. When this filter is at the end of its lifespan, it will slow down the water coming into your home. Depending on your home’s water demand, you may find that you need to change your sediment filter more frequently than our above recommendations. 


The second filter of your disinfection station is the carbon filter, used to condition the water, improving taste and odor. We use a 10-micron nominal carbon filter on our systems. 

Like the sediment filters, how often you change the carbon filters depends on the filter size and demand. We typically recommend systems of 2.5 – 4.5×10 be changed quarterly and larger 4.5×20″ carbon filters changed 2x a year. 

This excellent chart from illustrates micron sizes and how they relate to the particles we’re removing.


Your ultraviolet light is the most critical part of your filtration system. Not only does it antibacterialize your water, but it also provides a potable supply without the use of chemicals like chlorine. 

These UV bulbs are typically rated for 10,000 hours and we recommend changing them annually. Although the bulb may continue to shine, the intensity of the light output will gradually decrease, as will its ability to disinfect your water. Read more about why we use UV light to disinfect rainwater here.

After you have completed the steps above, you have completed the maintenance of your rainwater harvesting system! 

Many of our customers enjoy being intimately familiar with their rainwater and opt to maintain their own systems. We sell filters and UV bulbs at our Dripping Springs location. 


Harvest Rain offers annual service agreements, even on systems we did not originally install. During a service maintenance appointment, our tech will complete the leaf basket cleaning, filter, and UV changes (when needed), as well as visual inspections of the gutters, downspouts, tank, pad, pump, and pressure tank. Contact our friendly service team below to schedule.


Rainwater systems used solely for irrigation water (i.e., nonpotable) do not employ as extensive a filtration system as potable rainwater collections; hence their upkeep is less involved. However, regularly checking the gutters, leaf guards, and leaf basket at the tank will help protect your irrigation system’s longevity. 


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