Permeable pavements are a sustainable and environmentally friendly alternative to traditional pavement. Traditional pavements, like concrete and asphalt, are impermeable. When it rains, water can't penetrate these surfaces and runs off the pavements into a drainage system where it can cause flooding and erosion, as well as carry pollutants into our waterways.

Permeable pavers are specially designed to allow water to pass directly through the surface and infiltrate into the ground below. They can take several forms, from permeable asphalt or concrete to permeable pavers, which look just like regular pavers, but they have spaces between them, allowing water to flow through.

When rainwater falls onto a permeable pavement, instead of running off, it flows off the surface through the openings or pores in the pavement. Beneath the surface, there's a layer of stone that acts as a water reservoir. This reservoir stores water temporarily, allowing it to slowly infiltrate into the soil below.

Permeable pavers reduce stormwater runoff, minimizing the risk of flooding and improving water quality by filtering out pollutants as water passes through the layers. Additionally, they can help reduce the urban heat island effect, reducing the temperatures in our cities, making them more sustainable and comfortable. By choosing permeable pavers, we can contribute to creating more resilient and eco-friendly communities.

Permeable pavement is a simple solution for eco-friendly, sustainable stormwater management. But, to ensure it works effectively, regular inspections are essential.

The first step is a visual inspection. Walk across the permeable surface and look for any visible damage, like cracks, uneven settling, or displaced pavers. These issues can compromise the system's efficiency.

Next, check for debris or signs of clogging on the surface. Sediment, mulch from landscaped areas, as well as leaves and dirt cany accumulate and block the permeable openings, leading to puddles and problem spots. Also, check for cracks, deterioration, and other damage to the pavers.

It can be useful to inspect the pavement after it rains, looking for areas of standing water. You can also perform an infiltration test by pouring water onto the pavement using up to five gallons of water. If it isn't draining within a reasonable time, there might be a problem.

If you find problem areas in a permeable paver system, you might try to remove a block and inspect the underside of the system. Look for solid sediment or issues with the stone base. If you can’t access the underside, a professional can inspect and test it for you.

If you’re seeing lots of standing water or there are unusual changes or damage to the above-ground parts of the system, consider calling a stormwater professional to do an inspection and some investigation. They can help determine what is going on and come up with a plan to remedy any problems you’re having.

Regular inspections and maintenance ensure your permeable pavement continues to function optimally, minimizing flooding, preventing runoff, and contributing to a healthy watershed.

After significant rainfall, observe the observation well for three consecutive days. If standing water remains after those three days, that is a clear sign of a clogging issue. You can also pour water from a bucket onto the surface to test whether infiltration is working as it should. If the water does not drain within a reasonable time, there may be a problem with the surface or subsurface layers.

Inspect inlets, pre-treatment cells, and any flow diversion structures for sediment buildup and structural damage. Check the condition of the observation well and ensure it is properly capped. Examine the contributing drainage area for sediment buildup and erosion that could contribute material to the permeable surface.

Permeable pavement is a fantastic solution for sustainable stormwater management, but it requires proper maintenance to ensure it stays effective.

If you’ve done an inspection – or had one done for you – that has identified some problems that need attention, or if you’re seeing standing water on the pavement after it rains, Exact can help. There are several different types of permeable pavements, and each one requires a different technique and equipment to clean it correctly. The key is to get the pavement clean without causing damage to the system.

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For the first six months following construction, the system and its contributing drainage area should be inspected at least twice after any significant rainfall. The pavement surface should be vacuumed with a standard or regenerative street sweeper two to four times per year, depending on rainfall volume, to prevent clogging. Accumulated sediment on the pavement surface should be removed promptly. Damaged or deteriorating sections of the pavement surface should be repaired or replaced.

For grid paver systems, grass should be mowed at least once every one to two months during the growing season. Annual maintenance should include a routine inspection and weeding. Every two to three years, accumulated sediment in pre-treatment cells and inflow points should be removed. If the system becomes severely clogged, a regenerative street sweeper may be required, and joint material between pavers may need to be replaced.

There are several different types of permeable pavement, and the exact installation process for each will vary from one system to the next. There are, however, several components that are pretty common.

The first step usually includes excavating the installation area and till the soil beneath the system to encourage infiltration. The depth of the excavation should include the height of the paver and the depth of the stone base. All permeable pavements rely on a structural base to help support the weight of people or vehicles, so the heavier the load, the more depth will be needed. The stone also serves as a reservoir for the runoff that soaks through the pavers, so most systems rely on a washed stone that’s free of sediment.

Some permeable pavement systems will include a high flow fabric between the soil and the stone base. Stone is place on the fabric (or native soil) and compacted. Compacting the stone is important to make sure it’s stable and doesn’t settle over time, which can make the pavers look uneven.

With the base prepared, the permeable pavers are carefully laid according to the predetermined design. Multiple colors can be mixed to create patterns, and edge blocks often have to be cut to account for curves or special edging designs.

Some systems will require small chip stones to be swept into the joints between pavers, helping to stabilize the blocks. Finally, check the surrounding area to ensure all the areas contributing runoff onto the pavement are stabilized with good vegetation or mulch, as you don’t want any erosion and sediment to prematurely clog up your new permeable pavement.

The most obvious sign is standing water on the pavement surface after rainfall. You can perform a simple test by pouring five gallons of water onto the surface. If it does not drain within a few minutes, clogging is likely. Other indicators include visible sediment deposits on the surface, staining, or areas where pavers have settled unevenly. If you observe standing water after rain events, contact Exact Stormwater at (804) 302-5151 for a professional evaluation.

The pavement surface should be vacuumed with a street sweeper two to four times per year to prevent sediment from accumulating and clogging the pore spaces or joints. The exact frequency depends on the amount of sediment generated by the contributing drainage area and the local rainfall patterns. The contributing drainage area should also be stabilized to minimize sediment input.

Common types include pervious concrete, porous asphalt, interlocking concrete pavers with permeable joints, and grid pavers (plastic or concrete grids filled with gravel or grass). The choice of material depends on the intended use, traffic load, aesthetics, and the engineering design requirements. All types share the same fundamental principle: allowing water to pass through the surface and into a subsurface stone reservoir for temporary storage and infiltration.