Permeable Pavers Pros and Cons: Stormwater, Upkeep and Winter

The biggest permeable pavers pros and cons come down to one trade: rain soaks through stone-filled joints into a stone reservoir instead of running off, but that reservoir means a deeper dig, and the joints need cleaning to keep working. On soil that drains, with an owner who vacuums twice a year, they do what they promise; on tight clay next to a basement, they need a drain, a liner or a different plan.

How permeable pavers differ from regular pavers

A standard paver patio sits on sand bedding over a compacted dense-graded base, and its joints are filled with sand. CMHA’s PICP maintenance guide notes that sand joints and bedding let very little water in, so most rain runs off the surface. Our standard (non-permeable) patios get 6 inches of compacted 2A modified, more on clay or wet ground; our guide to paver base depth explains why. A permeable system leaves that dense base out.

Permeable interlocking concrete pavement (PICP) uses no sand either. Every layer is clean, open-graded crushed stone. CMHA’s PICP construction tech note describes the layers:

Layer	Standard pavers	Permeable pavers (PICP)
Joints	Sand	Angular No. 8, 89 or 9 stone
Bedding	Sand	2 inches of No. 8 stone
Base	Compacted dense-graded stone	Open-graded No. 57 stone, at least 6 inches for patios and walks, over No. 2, 3 or 4 stone where storage or traffic needs it
Soil underneath	Compacted	Generally left uncompacted so it can absorb water
Where rain goes	Mostly off the surface	Through the joints into the stone

The stone holds water in its voids while it soaks into the soil. Over slow-draining soils, a perforated underdrain carries the extra away. Geotextile lines the sides to keep soil out of the stone.

The pros

It handles stormwater on site. Compared with a hard surface, the Minnesota Stormwater Manual says properly designed and maintained permeable pavement can reduce runoff volume, suspended solids, phosphorus and runoff temperature, along with nitrogen, metals and oils. CMHA puts surface runoff reduction at up to 100 percent, depending on design.

It can take roof and driveway runoff. CMHA allows hard surfaces up to five times the permeable area; the Minnesota manual generally caps it at twice, or five times for roof or pretreated runoff.

No puddles, less ice. Meltwater drains into the joints instead of sitting on top. CMHA cites 2020 University of Toronto research finding that permeable pavers can eliminate refreezing into black ice and need a much lower salt rate than asphalt. The Minnesota manual says permeable pavements need significantly less deicer, and sometimes none.

It’s durable and repairable. CMHA gives the paver units a 50-year design life. It’s ready for traffic when built, and units lift out for repairs.

CMHA notes some towns credit permeable surfaces against stormwater fees; ask yours.

The cons

A deeper dig and more stone. A permeable patio needs at least 6 inches of No. 57 base plus 2 inches of No. 8 bedding under the pavers, and more if the design has to store a set amount of water. CMHA says the base is sized for both storage and traffic, and the thicker answer wins. More digging and more washed stone mean more cost up front.

Upkeep is not optional. Dirt, leaves, grass clippings and mulch load up the joints the way dust loads an air-conditioning filter, as CMHA puts it. The Minnesota manual calls for vacuuming at least twice a year, and its maintenance guidance gives a rule of thumb of 3 to 6 percent of the installation cost per year for upkeep.

Soil and site limits. These come straight from the design guides:

• Clay soils (NRCS hydrologic soil groups C and D) usually need an underdrain, per the Minnesota design criteria. In most cases it shouldn’t sit on fill soils.
• CMHA wants more than 2 feet from the bottom of the base to the seasonal high water table. Minnesota requires 3 feet, so check your local rule.
• Keep it at least 10 feet from foundation walls with no waterproofing or drainage. CMHA prefers it downhill from the house, with piped footing drains and an impermeable liner on basement walls next to it.
• Surface slope under 12 percent, typically 5 percent or less.
• No fuel or chemical storage on it, and keep it at least 100 feet from water supply wells.

Wide openings can be hard underfoot. EPA’s permeable pavement fact sheet notes that units with large stone-filled openings can be tough on wheelchairs, bikes and high heels. CMHA keeps joints at 1/2 inch or less for ADA.

Permeable paver driveways

CMHA recommends PICP for residential driveways. Vehicle areas use pavers at least 3 1/8 inches thick, over 4 inches of No. 57 base and a No. 2, 3 or 4 stone subbase sized for traffic and storage. On a home driveway the subbase can sometimes be dropped in favor of a thicker base.

Plowing is fine. CMHA says to use steel or hard rubber blades (steel scratches any paving), get your snow contractor to confirm protective edges in writing, and fit snow blowers with plastic on the scoops. The Minnesota manual suggests setting the blade about 1/2 inch higher than normal. Push dirty snow onto the lawn, not onto the pavers.

How they hold up in cold climates

They hold up well when built right. The Minnesota manual reports favorable performance in cold climates: the air in the stone base insulates, delays frost and reduces frost depth while the pavement keeps draining. That counts in freeze-thaw country like central Pennsylvania, where we build.

Two winter rules:

• No sand. CMHA, the Minnesota manual and EPA all say not to sand permeable pavers for traction. Use joint stone instead; some of it works into the joints by spring.
• Pick the right salt. CMHA lists sodium chloride, calcium chloride and potassium chloride as acceptable when used sparingly, and says never to use magnesium chloride or anything with ammonium nitrate or ammonium sulfate. Our salt on pavers guide compares ice melts.

What maintenance looks like

When	What to do
Weekly during mowing and leaf season	Sweep or blow clippings, leaves and mulch off the surface
3 to 6 months after install	Refill joints as the stone settles
Spring and fall	Vacuum the surface and joints, then top up joint stone to the bottom of the paver chamfers
During or after a storm	Look for ponding. Ponding on more than 20 percent of the surface means it’s due for cleaning; water standing more than 15 minutes marks a spot that’s starting to clog
As needed	Vacuum out the dirty top of the joint stone and refill with clean stone

For areas under 2,000 square feet, CMHA lists a broom, a leaf blower (at least 120 mph air speed), a rotary brush or a wet/dry shop vacuum. A pressure washer blows joint stone out and isn’t the best method alone. Slope lawns and beds away from the pavers, and never pile mulch or topsoil on them.

Are permeable pavers worth it?

They’re worth it when you have a real water job for them: a tight lot with nowhere else for runoff, a stormwater or impervious-cover rule to meet, or a patio that always puddles. Sandy or gravelly soil, or a place to run an underdrain, makes the case stronger.

Rethink them when the soil is heavy clay with no outlet, the area sits right against a basement, the slope is steep, or the space collects runoff from lawn and beds. The Minnesota manual designs permeable pavement mainly for rain that falls on it, so it won’t fix a soggy yard. If water is the real problem, start with why your yard holds water after it rains, or have our backyard drainage plan map where it should go.

DIY or hire a pro

A small permeable walk on sandy soil is a fair DIY job if you rent the right compactor and keep every pile of stone clean. CMHA calls a 13,500 lbf reversible plate compactor best practice for the base, and keeping sediment out the highest priority.

Hire a pro for driveways, clay soils, underdrains, anything near a foundation and any install tied to a stormwater permit. CMHA runs a PICP specialist course; ask if the installer has taken it.

Frequently Asked Questions

Can you use polymeric sand in permeable pavers?

No. Permeable pavers get angular No. 8, 89 or 9 stone in the joints, because sand lets very little water through. Our guide to polymeric sand vs regular sand covers sand for standard pavers.

Do permeable pavers need a drain?

Over sand and gravel they often don’t. Over clay soils, the Minnesota Stormwater Manual says an underdrain is usually required, and every design needs an overflow route for big storms.

How long do permeable pavers last?

CMHA gives the paver units a 50-year design life. The Minnesota Stormwater Manual says the system can operate effectively for up to 30 years when it’s maintained.

Do permeable pavers get weeds?

Only where sediment has built up in the joints, according to CMHA. Weeds are a sign the surface is due for vacuuming, and they should be pulled by hand.

Sources: CMHA, PAV-TEC-018 Construction of Permeable Interlocking Concrete Pavement Systems; CMHA, PAV-TEC-023 Maintenance Guide for Permeable Interlocking Concrete Pavements; Minnesota Stormwater Manual, Overview for permeable pavement; Minnesota Stormwater Manual, Design criteria for permeable pavement; Minnesota Stormwater Manual, Operation and maintenance of permeable pavement; U.S. EPA, Stormwater Best Management Practice: Permeable Pavements (EPA-832-F-21-031W)

Published by Muthler Landscaping & Construction, owned by Thayne Muthler (PA HIC #PA212584). How we research and check facts: editorial policy.