Drywell/Stormdrain Maintenance

StormWater Pros offers maintenance services for drywells to property owners, property managers, developers, contractors, engineers and others. However, the maintenance services are not limited to only drywells. StormWater Pros offers cleaning/maintenance services for other storm structures such as catch basins, headwalls, culverts, underground storage tanks, leach pits, French drains, storm drain pipes, scuppers areas, drainage rip rap, StormTech Systems, separation chambers, and much more. In addition to our maintenance services StormWater Pros offers drainage evaluations for properties that don’t drain correctly or have nuisance drainage issues. Our engineering staff can propose cost-effective engineered solutions to help solve your drainage issues. Please refer to the “Engineering Consulting” page for further information

Maintenance Services Include:
*Annual Inspection/Service Agreements

The maintenance process begins with an Initial Inspection of the drywells or other drainage structure. During this inspection an assessment of the drywell or drainage structure is performed. The amount of accumulated silt & debris needing removal is estimated along with any associated repairs needed to internal piping, concrete, screens, or grate covers. This assessment is recorded in an inspection report that is provided to the customer. A color coded site map showing all the drywell and drainage structure locations is also provided to the customer for future maintenance and reference purposes. Finally, the customer is provided with a cost proposal for all cleaning & repairs needed.


After the initial inspection and approval of the cost proposal, StormWater Pros performs the Cleaning/Maintenance Work with use of specialized machinery and trained staff. Silt and debris removal is performed by the use of hydrovactor truck that utilizes high water pressure and suction power for the removal. All settling chambers are properly cleaned and any associated or attached storm drain pipes are cleaned using a jet rod attached to the hydrovactor truck. All silt & debris removed is properly disposed of off-site. Any hazardous materials encountered are disposed of at a properly permitted site. Drywell maintenance also includes replacement of the geotextile fabric and oil absorbent pillows. The geotextile fabric is located at the bottom of the settling chamber and protects the drywell gravel pack. Drywell and storm structure grates and covers are properly replaced and secured when the cleaning/maintenance services are complete. StormWater Pros provides the customer with a detailed “Clean Report” showing the amount debris removed, pictures of the cleaned systems, and any further repairs needed to keep the system storm structure grates and covers are properly replaced and secured when the cleaning/maintenance services are complete. StormWater Pros provides the customer with a detailed “Clean Report” showing the amount debris removed, pictures of the cleaned systems, and any further repairs needed to keep the system is proper operational condition.


Repairs to drywells or drainage structures are critical to keeping them in the proper operational condition and to keeping properties draining correctly. Possible repairs to drywells include but are not limited to the following; debris screen replacement, bracket replacement for a leaning standpipe, concrete liner gaps, standpipe replacement, concrete collar repair, ring & grate replacement, ring & grate elevation adjustments, injection pipe evaluation, soil subsidence (aka sink hole) around the chambers, and much more. Repairs to other drainage structures include catch basin grate replacement, tank or pipe sealing, trash rack repair & replacement for headwalls, sump pump replacement, and more. StormWater Pros is willing to provide cost estimates for any of these repair needs.

StormWater Pros offers Annual Inspection/Service Agreements. We will schedule annual inspections of your drywells and other storm structures. Associated costs for inspection are applied to maintenance pricing so the inspection is free each year when maintenance is needed. In some cases we determine what the annual maintenance pricing is and lock into that pricing for an agreed upon time period.


Subsection 2– Drywell Installation

StormWater Pros has the ability to install new drywells for property owners, property managers, developers, contractors and others. A drywell is an underground structure that disposes of storm water by percolating the water into the soil. Drywells receive water directly from a surface or connected invert pipes and use the influence of gravity and head pressure. Some drywells are simply excavated pits backfilled with gravel or rip rap. More advanced drywells contain a large interior storage volume with a use of precast concrete chambers. New dual chamber systems use two (2) concrete chambers with one being used a filtration chamber to protect the actual drywell chamber.

StormWater Pros’ series of Purewell drywell designs maximize performance and longevity along with added affordability. Full drywell design details are available for reference and plan specification for engineered drawings. Our mini-drywell design is excellent for existing sites looking to solve minor drainage issues. Please contact us to see how our drywell designs can best meet your needs.
*Need to attach CAD and PDF files of drywell designs

Subsection 3– Drywell Registration

ADEQ (Arizona Department of Environmental Quality) regulations state that all drywells need to be registered with the ADEQ. StormWater Pros performs this required registration for new drywells and old, unregistered drywells. Upon request we can verify if any existing drywells on a property are registered with the ADEQ. Should registration be needed, StormWater Pros can prepare and submit the necessary documentation to properly register your drywell.

Subsection 4– Drywell Abandonments

The ADEQ (Arizona Department of Environmental Quality) has specified closure procedure to follow to abandon drywells. Abandonment is sometimes required when sites are re-developed, facilities change, or simply the drywell is no long needed. StormWater Pros can ensure the proper abandonment procedure is followed and performed in the abandonment of your drywell. We can also submit all the necessary documentation to the ADEQ to ensure it is properly closed out with the ADEQ. Please contact us for a cost proposal for this service.

Subsection 5– Drywell Percolation Testing

A drywell percolation test is performed by injecting a certain amount of water into a drywell to help determine the rate at which the drywell percolates water into the ground. The rate at which the drywell percolates water is called the drywell’s “Percolation Rate”. These tests are performed by using either the “Constant Head” or “Falling Head” methods. These percolation rates give users a good idea of functionality of the drywell. Some municipalities require percolation tests to be performed on newly installed drywells. By performing percolation tests on existing drywells an owner can know if the drywell is still in proper operation. Each percolation test is monitored by our engineering staff and comes with a detailed report that determines final percolation rates. Reports are stamped and approved by a licensed engineer should that be desired or required by the local municipality. Please contact us for cost proposals for this service.


Subsection 6– Existing Drywell Retofit

Many drywell owners or users do not understand that each drywell has a defined life-span. The life-span of a drywell can depend on volume, application, and consistent maintenance. Lack of maintenance for drywells in certain applications can dramatically shorten the life span of a drywell. In our experience, single-chamber drywell systems in asphalt driveways meet this criteria. For this reason, many municipalities shy against this type of drywell application in their design manuals.

Drywells that have met or are near the end of their life-span tend to drain water at slower rates and leave standing water for longer periods of time in the drainage area. Unfortunately cleaning & maintenance cannot always successfully restore the drywell to proper operation. Fortunately through the “retrofit” process these older single chamber systems can transformed into dual chambers systems with an install of a new adjacent drywell. In this process, the new adjacent drywell is connected to old chamber via PVC piping. The old drywell becomes a filtration chamber with a filter screen and all water sent into the new drywell to be disposed of into the ground. We are able to make adequate use of the old, nonfunctioning drywell and provide a new system with a longer life span. Should you need an evaluation of an old drywell draining water at slower rates, please contact us for our professional evaluation.


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