Buffer Strips for Water Quality

What is a buffer strip?

A buffer strip, or riparian buffer when it runs along a stream, is a strip of grass, shrubs or trees left or planted between a field, pasture or lot and a waterway. The plants slow water and hold soil in place.

Buffers can also shelter wildlife, shade streams and reduce bank erosion. They come in many forms, from simple grass strips to layered plantings of trees and shrubs.

Buffers also give you a place for pollinators and birds when they are planted with a mix of flowering plants, and they may help with flood damage along streams.

How do buffers protect water?

As runoff moves through the plants, flow slows, sediment drops out and some nutrients are taken up or held in the soil. Roots stabilize banks, and shade keeps streams cooler, which helps fish and other aquatic life.

Buffers work best when water moves across them in a thin, even sheet. If water concentrates in a gully and rushes through, the buffer cannot do its job, so fix the flow at the source.

Do not mistake a buffer for a licence to apply more nutrients on the field above it. The buffer is a safety net, and it works best alongside careful nutrient and manure management. Maintenance keeps the buffer effective. A buffer clogged with sediment or damaged by tire ruts loses much of its power, so repair damage promptly and keep equipment out.

• Slow runoff and trap sediment
• Take up some nutrients
• Stabilize banks
• Shade and cool the stream

How wide should a buffer be?

There is no single answer. The best width depends on slope, soil, the water body, what is upslope and your goals. Wider buffers generally do more, but even a narrow strip is better than none.

Your NRCS office, conservation district or extension office can recommend widths and plant types for your site. Program rules may set minimums if you take part in cost-share, so ask before planting.

Slope matters. Steeper land sends water faster, so a wider or more layered buffer may be needed, and gullies need fixing first. A conservation technician can walk the site with you.

• Slope of the land
• Soil type
• Water body and what is upslope
• Your cost-share program rules

What should I plant?

Choose plants suited to your climate, soil and moisture. Deep-rooted native grasses, shrubs and trees are common choices. Mixing plant types gives better cover and habitat.

Ask local conservation staff for plant lists and sources. Avoid species that spread aggressively or are considered invasive in your state, and check that nothing you plant is harmful to your livestock.

Seed and plants need the right timing, which depends on your frost dates and soil moisture. Ask local conservation staff what planting windows suit your area. Layered plantings, with grasses closest to the field, shrubs in the middle and trees nearest the water, give the best mix of filtering and habitat, though what is practical depends on space and the rules in your area.

• Grasses nearest the field
• Shrubs in the middle
• Trees nearest the water
• Native species where available

How do I look after a buffer?

New plantings need protection and care for the first years: weed control, watering in dry spells and protection from browsing animals and mowing. After that, buffers need less work but still need checking.

Fix gullies, remove built-up sediment if it smothers plants and keep livestock out unless a plan allows grazing. Avoid spraying chemicals into the buffer, and check labels for restrictions near water.

Buffers can also be grazed or hayed in some programs and plans, but that changes how well they protect water. Check the terms before you do either.

• Weed control while plants establish
• Protection from browsing and mowing
• Gully repair
• No spraying into the buffer

What about rules, cost and help?

Rules on stream setbacks, stream-side disturbance and buffers vary by state, county and watershed. Before planting or clearing near water, ask your county and state environmental agency whether permits are needed.

Cost categories include plants, site preparation, fencing, labor and upkeep. Cost-share programs through NRCS or conservation districts may help, with rules that change by year and location. Ask what is open to small farms.

Before you start, take photos of the site and write down your goals, so you can measure change in a few years.

• Planting and site preparation
• Fencing to protect the buffer
• Labor and upkeep
• Possible cost-share, with rules that change

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.