Skip to Content

WLS-017 Landscape Guidelines for Non-Standard Septic Systems

Permit and Resource Management Department Banner 750

Version: 06/19/2023

Landscaping guidelines for nonstandard septic systems.

Vegetative cover is intended to prevent erosion of the soil over non-standard septic systems such as mound, at-grade and pressure distribution systems. It also assists with a natural means of evapotranspiration of the sewage effluent from the system. These types of septic systems create a special set of conditions due to the way they function. The placement of the gravel bed creates a drought area directly on the top of the mound while the application of effluent produces wetter than ordinary soils immediately below. Since non-standard septic systems tend to be relatively dry on top, they are most conducive to planting native grasses, herbaceous plants, various bulbs, succulents, herbs and other ornamental ground covers that are drought resistant or drought tolerant.

All plants covering a non-standard septic system shall be drought resistant and have non-invasive root systems to prevent damage and/or failure of the septic system. Attached is a suggested list of various plants suitable for planting directly on your non-standard septic system. This is only a partial list, and you may want to consult a landscape professional for other plant selections. This professional should be advised of the non-standard septic system.

  • Vegetation management is essential to proper maintenance and monitoring of these types of systems.
  • Do not plant trees or large shrubs directly on a mound or at-grade system or within the area of any non-standard leach field.
  • Do not plant a lawn that requires heavy watering, such as bluegrass. It is best to plant drought tolerant grasses such as various types of fescues.
  • Do not plant ivy or ice plant as they retain moisture thereby restricting evapotranspiration which will keep the system too wet. Ivy and ice plant both have very invasive root systems and are prohibited on any type of septic system.
  • Do not use overhead “Rainbird” type sprinklers. The irrigation method of choice is drip irrigation which will minimally provide enough irrigation for the plants while keeping the system as dry as possible.
  • Do not promote activities on the system that will add to soil compaction and loss of absorption capacity.
  • Do not drive across the system.
  • Do not cut or mow vegetation when the soil is wet. Remove clippings promptly.
  • Do not allow large animals on the system area.
  • Do not cover valve boxes and performance wells.
  • Do not operate equipment on system when soil is wet.

Please Note: Heavy equipment or vehicles driven over the system may damage it.

Suggested Plant List for Non-standard Sewage Disposal Systems

Herbaceous Plants

Color Key: B = Blue, O = Orange, P = Pink, PUR = Purple, R = Red, W = White, Y = Yellow
(↓↑ Sort Column Alphabetically or Numerically: Select the column title of the column you want to sort.)
Common Name Scientific Name Color Height Comments
Yarrow Achillea species Y,W,R 12 inches fire retardant
Cape Weed Arctotheca calendula Y 6 inches spreads
Silver Mound Artemesia schmidtiana Y 2 feet  
Bachelor's Buttons Centaurea cyanus B,P,R,W 1-2 feet  
Cosmos Cosmos bipinnatus R,Y 3-6 feet easy
Yellow Cosmos Cosmos sulphureus Y 3-4 feet easy
Monkey Flower Diplacus species many 1-3 feet  
Fortnight Lily Dietes iridiodes W 4 feet tough
Fleabane Erigeron karvinskianus W,P 1-2 feet drought tolerant
California Poppy Eschscholzia californica O,R 1-2 feet spreads
Blue Fescue Festuca ovina glauca B 12 inches spreads
Daylilies Hemerocallis species many 1-6 feet easy
Trailing Lantana Lantana montevidensis R 1-2 feet spreads
Sweet Alyssum Lobularia maritima W 6-12 inches spreads
Forget-Me-Not Myosotis sylvatica B 6-12 inches tough
Mexican Evening Primrose Oenothera species R,W,Y 1-2 feet profuse
Santolina Santolina species Y,W 1-3 feet aromatic
Lamb's Ears Stachys byzantia PUR 12 inches spreads
Nasturtium Tropaeolum majus O,R,Y,W 12 inches spreads
Verbena Verbena species varies 1-3 feet  
California Fuchsia Zauschneria californica R 1-2 feet drought tolerant


Color Key: B = Blue, O = Orange, P = Pink, PUR = Purple, R = Red, W = White, Y = Yellow
Common Name Scientific Name Color Height Comments
Naked Lady Amaryllis belladona P 3 feet hardy
Montbretia Crocosmia crocosmiiflora R 2 feet hardy
Iris Iris species many 1-2 feet drainage
Daffodil Narcissus species Y,W 1-2 feet reproduces
Tulip Tulipa species many 1-2 feet tough

Succulents & Herbs

Many to choose from, very drought tolerant

Woody Ground Covers

Color Key: B = Blue, O = Orange, P = Pink, PUR = Purple, R = Red, W = White, Y = Yellow
Common Name Scientific Name Color Height Comments
Ground Cover Manzanita Arctostaphylos uva-ursi W 1-2 feet to 15 feet
Dwarf chaparral broom Baccharis pilularis W 1-2 feet tough
various prostrate forms Ceanothus species B 1-2 feet spreads
various prostrate forms Cotoneaster species R 6-12 inches tough
various prostrate forms Juniperus species Y 1-2 feet spreads
Prostrate Rosemary Rosemarinum officinalis B 1-2 feet tough