What the City of Tacoma's artificial turf tip sheet says
Tacoma Planning and Development Services publishes a tip sheet on how its Stormwater Management Manual applies to artificial turf. Most turf companies never mention it, but it answers the questions homeowners ask about permits and drainage.
The short version: Tacoma defines artificial turf as a lawn area, and also as a pollution-generating pervious surface. It is not counted as a hard surface like a patio or driveway. Installing turf is a land-disturbing activity, so the stormwater minimum requirements can apply once the disturbed area is large.
- Minimum Requirements #1 to #5 apply when land-disturbing activity reaches 7,000 square feet or more. Turf installation counts as land disturbance.
- The soil quality and depth practice normally required for lawns (BMP L613) is not required for artificial turf, because the city says it is not practical.
- Replacing an existing natural lawn or landscaped area with turf is not a converted vegetation area, so Minimum Requirements #6 to #9 are not triggered for that area. The same applies to replacing a hard surface with turf.
- Converting native or unmaintained vegetation to turf does count as converting vegetation, which matters on larger projects.
- If the turf has underdrains that connect to a stormwater facility or pipe system, that system must be sized for the underdrain flows too.
Do you need a permit to install artificial turf in Tacoma?
For a typical front or back yard, usually not, but check two numbers. Tacoma's permit guidance requires a site development permit for grading or fill over 50 cubic yards, or for disturbing 7,000 square feet or more of land. The grading exemption does not apply in critical areas, such as steep slopes or near wetlands and streams.
Excavation adds up faster than people expect. Digging out four inches across about 4,000 square feet removes roughly 50 cubic yards of soil. A deeper base, or regrading a sloped yard flat, reaches the number sooner. We calculate the excavation volume in the quote so you know which side of the line you are on.
Outside Tacoma city limits, the agency changes. University Place, Lakewood, Puyallup, Gig Harbor, and unincorporated Pierce County each apply their own codes. If you live in an HOA, check your covenants for turf rules before you order material.
What goes under artificial turf in western Washington
Turf backing is perforated or fully permeable, so water passes through the turf easily. The question is what happens next. On sandy, gravelly outwash soils, water soaks in fast. On clay or dense glacial till, it sits on top of the dense layer, saturates the base, and the turf feels spongy, smells, and grows moss at the seams.
A turf base built for this climate has these parts. The exact depths come from the soil test and the use, not a fixed number.
- Excavation: remove sod, roots, and organic topsoil. Organic soil left under turf keeps decomposing and settles unevenly.
- Grade the subgrade itself with a fall, so water that reaches it flows to an outlet instead of ponding.
- Separation fabric between the native soil and the base, so fines do not migrate up into the rock.
- Compacted crushed rock base, placed and compacted in lifts.
- A fine leveling layer on top, compacted smooth so seams and edges stay flat.
- On tight soils: a perforated drain line at the low edge, with an outlet to a legal discharge point. Do not point it at a neighbor or the house foundation.
Artificial turf for dogs in a rainy climate
Dog areas are where turf in the Puget Sound region is either a success or a smell problem. In the wet months, rain rinses the turf for you. In July and August, it does not, and urine that sits in the base is what causes odor.
The fixes are physical. The base must drain fast all the way down, which is one more reason clay sites need a drain line. Choose a turf with a fully permeable backing for heavy-use dog runs, and an infill made for pets. Put the main potty zone where a hose reaches it easily, and rinse it on a schedule in dry weeks.
Dogs also dig and race along the fence. Anchor the edges well, and put a paver or gravel border along fence lines where dogs run the same path every day. That edge takes the wear instead of the turf seam.
Shade, moss, and fir needles
Turf does not need sun, which is why it appeals in yards under big Douglas firs and maples where grass will not grow. But shade plus damp plus organic debris is exactly what moss needs, and it will root in the debris that collects in the turf fibers.
Keep debris off. In fall, blow or rake leaves and needles every week or two instead of letting them break down in place. Keep the north side of the house and the strip under eaves clear. If moss starts at the edges, that usually means the base is staying wet there, so look at drainage before you treat the surface.
Under very heavy shade, consider pavers or a gravel patio for the darkest spot and turf where some light reaches. That split often works better than turf wall to wall.
Turf, pavers, or real grass: a decision checklist
We install both turf and pavers, so we have no reason to push one, and sometimes the honest answer is to keep the grass. Use this list to decide.
- Turf fits: dog runs, play areas, shaded lawns that die out, small urban yards where mowing is a chore, and side yards.
- Pavers fit: anything with chairs, a table, a grill, or regular foot traffic in one path. Turf wears where people walk the same line.
- Real grass fits: large sunny lawns, homeowners who want the lowest upfront cost, and areas that must absorb a lot of roof runoff.
- Think twice about turf on steep slopes, in low spots where water collects, and right next to a south-facing wall where heat builds up.
- Mixed yards work well: a paver patio by the house, turf beyond it, and a clean edge between them.
Edges, seams, and transitions to pavers
Most turf that looks bad after a few years failed at the edges and seams, not in the middle. Seams must be cut along the same blade direction, joined on seam tape over a flat base, and kept out of the main walking path where possible.
Where turf meets a paver patio or walkway, the paver edge restraint does double duty. It holds the pavers and gives the turf a straight, solid edge to tuck against. Set the turf slightly below the paver surface so a mower, a broom, or a leaf blower does not catch the edge. On a combined project we build the paver base and the turf base so they drain in the same direction.
What drives the cost of artificial turf installation
Turf pricing on the internet is usually for the turf material. The base and the drainage are most of the work on a Tacoma lot. These items move the number, and the free on-site quote lists them separately.
- Total area, and how many seams the layout needs.
- Excavation depth and the volume of soil hauled away.
- Soil type: clay and till sites need more base or a drain line.
- Turf product and infill, especially for dogs.
- Access for machines versus hand work through a side gate.
- Edging, borders, and any paver transitions.
- Removing old lawn, roots, stumps, or concrete.
Questions to ask any turf installer
Ask every bidder the same questions and compare the answers, not just the price.
- How deep do you excavate, and what goes back in, layer by layer?
- Do you install separation fabric under the base?
- Where does water go on my soil if it does not soak in?
- How do you secure the edges along fences, beds, and patios?
- Is your crew in-house or subcontracted? ND installs with its own crews.
- Does my project need a site development permit, and how did you calculate that?