Does water stay on artificial grass?

With the widespread use of artificial turf, people are paying increasing attention to its performance. Many people choose artificial turf because of its year-round greenness and maintenance-free nature. However, a common question arises: Will artificial turf itself accumulate water?

Layered structure

To understand whether artificial turf will accumulate water, you first need to understand its basic structure. 

* Artificial turf grass fibers: The grass fibers in artificial turf are mostly made of polyethylene (PE) or polypropylene (PP), which do not absorb or retain water. More importantly, the grass fibers are fixed to the backing fabric through a tufting process, forming dense gaps. These gaps act like countless "micro-channels," allowing rainwater to quickly pass through the surface and preventing it from accumulating on the grass fibers.

* Adhesive and Drainage Holes: The backing fabric beneath the grass fibers is the core of drainage. High-quality backing fabric has evenly punched drainage holes beforehand. The adhesive backing serves to secure the grass fibers while ensuring the drainage holes are not blocked. Qualified adhesive backing uses an "open-hole design" with an open-hole rate of ≥85%, forming "vertical waterways" that penetrate the backing fabric, allowing rainwater passing through the grass fibers to seep downwards without obstruction.

* Base layer: The base layer beneath the substructure is typically composed of 10-15cm thick gravel or crushed stone. This layer serves to temporarily store and disperse water – after rainwater penetrates the substructure, it first enters the gaps between the gravel, preventing localized water accumulation; simultaneously, the loose structure of the gravel layer allows rainwater to quickly spread outwards, flowing towards the slope of the foundation.

* Foundation: Beneath the base layer is compacted soil with a compaction degree of ≥95%, which is the last guarantee for drainage. The foundation must be designed with a drainage slope of 1-2% to guide rainwater diffused through the base layer to flow in a designated direction and eventually flow into the drainage ditches around the site or seep naturally into the ground.

Drainage path

After a rainfall, the flow path of the rainwater is clearly visible:

Rainwater falls on the surface of the artificial turf → passes through the gaps between the grass fibers → enters the gravel base layer through the drainage holes in the backing fabric → disperses and infiltrates in the gaps between the gravel → flows directionally along the pre-set 1-2% slope of the base → eventually flows into the drainage ditch or naturally infiltrates into the underground soil.

The entire process will not result in significant water accumulation under standard installation conditions.

Why does water sometimes accumulate?

1. Construction quality

Construction quality is a key factor affecting drainage performance. Even if the lawn itself has good drainage, water can easily accumulate if the foundation is not properly prepared.

(1) Inadequate Foundation Slope

Insufficient slope causes water to lose direction, which is the primary cause of water accumulation. The foundation must have a stable slope of 1-2% to guide water flow in a specific direction. If the slope is insufficient, completely flat, or reversed, rainwater will not be able to form effective runoff and will only swirl around on the surface, eventually forming water accumulation in low-lying areas, especially in the center and corners of the site.

(2) Inadequate Base Material and Thickness

As the core structure for drainage, the material and thickness of the crushed stone layer are crucial. If crushed stone with too small a particle size and too much mud and dust is used, its gaps are easily blocked, turning the base layer into an impermeable layer. At the same time, if the base layer thickness is less than 8cm, its ability to retain and diffuse rainwater will be significantly reduced. During heavy rain, rainwater will not have time to infiltrate and will flow back upwards, forming surface silt.

(3) Clogged Drainage Holes

During installation, improper handling can easily clog the drainage holes on the back of the turf due to adhesive on the backing fabric, dust from the subfloor, or other debris. This hidden problem is difficult to detect after installation, but it directly prevents rainwater from seeping into the subfloor, causing water to be trapped on the turf surface and unable to drain.

2. Product Issues

Inadequate Drainage Hole Density and Design. Low-quality artificial turf, in an effort to save costs, reduces the number or size of drainage holes, or even distributes them unevenly, obstructing rainwater infiltration. Insufficient porosity in the adhesive backing of some inferior backing fabrics can also indirectly clog drainage channels.

Excessively High Grass Density and Lack of Combing. Higher grass density is not always better. If the grass density exceeds 20,000 stitches/m², and it is not combed promptly after installation, the grass fibers will be compressed, clogging surface gaps and hindering rainwater infiltration. This can cause temporary surface water accumulation, especially after rain.

3. Use and Maintenance

Long-term blockage by debris. During daily use, leaves, soil, pet feces, children's toys, and other debris will accumulate on the lawn surface. If not cleaned regularly, this will clog the gaps between the grass fibers and the drainage holes in the underlayment, preventing rainwater from penetrating.

Subbase settlement creating depressions. Over time, if the subbase gravel is not sufficiently compacted, uneven settlement may occur, forming localized low-lying areas. Rainwater will naturally collect in these small pits, unable to flow down the slope, leading to localized water accumulation.

4. Special Environmental Circumstances

Temporary water accumulation may occur if the site is located in a low-lying area, has poor drainage, or experiences extreme heavy rainfall. However, this is not a problem with the lawn itself, but rather a limitation imposed by the external environment.

How to ensure and optimize drainage

Whether you are preparing to install artificial turf or have already installed it and are experiencing water accumulation problems, you can solve them using the following methods:

1. Early prevention

Users preparing for installation should plan their systems carefully, select high-quality turf, and follow proper installation procedures. During planning, ensure the foundation has a 1-2% drainage slope and connects to the surrounding drainage system. When selecting materials, pay close attention to the drainage hole density, perforation rate, and third-party drainage testing reports of the turf backing. During installation, strictly use qualified infill materials, ensuring a base layer at least 10cm thick and fully compacting it to prevent water accumulation from the source.

2. Post-maintenance

To ensure long-term smooth drainage of installed artificial turf, daily maintenance requires the following three points:

• Regular cleaning: Remove surface debris weekly and rinse monthly with a low-pressure water gun to prevent clogging of the pores;
• Regular grooming: Brush along the direction of the grass fibers monthly to keep the fibers upright and the gaps clear;
• Timely inspection and maintenance: Check for water accumulation points after rain and promptly unclog drainage holes or add gravel to settle areas to adjust the slope.

Handling Special Circumstances

Temporary water accumulation may occur during extreme rainfall, which is normal. If the water does not recede within one hour after the rain, follow these steps:

• Quickly clear debris from the drain outlets;
• Use a high-pressure water gun to rinse the gaps between the grass fibers and the drain holes;
• If the water still has not drained, check for compacted subgrade or blocked drainage ditches. If necessary, contact the construction team to loosen the subgrade.

If the site is located in a low-lying area, the lawn's own drainage may be insufficient. Additional facilities can be added:

• Dig a 50cm deep drainage ditch along the edge of the lawn, lay infiltration pipes inside, cover with gravel, and backfill to guide rainwater to drain quickly;
• For areas with severe localized water accumulation, plastic drainage boards can be added under the lawn to improve vertical drainage speed.

In summary

whether artificial turf will accumulate water depends on whether the installation is standardized, whether the turf is compliant with regulations, and whether maintenance is adequate. By properly managing every step from planning, material selection, construction to maintenance, artificial turf can maintain good drainage. Whether in heavy rain or during long-term use, it can avoid the problem of water accumulation and continue to demonstrate its durability and aesthetic advantages.