FIELD NOTE · SUPPLEMENTAL SET
One year defined, three to five conceded: MWELO and the establishment period nobody has to watch
ISSUEDJULY 11, 2026DRAWN BY THE NIGHTLY SWEEP
Water on a finished commercial site goes where the controller sends it, and the controller runs whatever schedule was loaded on the last day of the job by a crew paid to be finished. That schedule was written for plants a few weeks old. The Model Water Efficient Landscape Ordinance, kept at Title 23, Chapter 2.7 of the California Code of Regulations and amended effective January 2, 2025, has a great deal to say about that schedule and nothing at all about who comes back and changes it.
The ordinance concedes the timescale in its own definitions and then declines to cover it. Section 490.2(a)(23) fixes the establishment period at the first year after installing the plant, or the first two years if irrigation will be terminated, and adds that most plants are typically established after one or two years while native habitat mitigation areas and trees may need three to five. The defined length is one year, or two. The concession is three to five, and it attaches to exactly the plants a commercial site gets judged on twenty years later.
One year on the page, three to five in the ground, and a single dated approval covering both.
The worksheet is where planting stops being planting and becomes a budget. MAWA equals ETo times 0.62 times ETAF times regular landscape area plus 1.0 times special landscape area, sections 490.2(a)(26) and 493.3(a)(1) cap ETAF at 0.55 residential and 0.45 non-residential, and ETo comes out of Appendix C, a table of annual inches: Long Beach 45.8, Palm Desert 70.9. A designer of record working both ends of that table knows which plan set gets argued about, and the argument is about palette, the one running underneath the region's turf conversion programs.
The soil management report is the only document in the package describing something with a memory, and section 493.1 wants texture, infiltration rate, pH, salts, sodium and organic matter. Where mass grading is planned it arrives at the end with the certificate, after the thing it sampled is gone. A plan checker approves or denies under section 491.3(b), and the file goes quiet for the length of a construction schedule.
All three irrigation schedules are written on one day and handed to a controller that has never seen a summer.
The handoff between the establishment schedule and the established-landscape schedule is not a date. Section 490.2(a)(22) defines the established landscape as the stage at which plants have developed significant root growth into the soil, which is a judgment somebody makes by going and looking, and no section requires anybody to go and look.
Section 493.6 sends a certified landscape irrigation auditor out once, and bars that auditor from being the person who designed or installed it, which is a real and well-drawn protection. On multi-installation projects, section 493.6(b) accepts one lot in seven. Under the prescriptive option there is no audit at all, which DWR said plainly in the Final Statement of Reasons for the 2025 rulemaking.
What that one visit measures is largely up to the agency, because section 493.6(c)(1) says the audit report may include, but is not limited to, inspection, system tune-up, system test with distribution uniformity, and reporting overspray or run off. The only inspection the chapter schedules is not required to test uniformity at all.
The 0.65 figure lives elsewhere. Section 493.2.2(e)(4)(B)(1) makes overhead irrigation systems document a low quarter distribution uniformity of 0.65 or higher using the protocol in ASABE/ICC 802-2020, a documentation duty on the emission devices discharged while the heads are plumb and the shrubs that will block them are still ankle high. Uniformity comes apart afterward, on clogged emitters, tilted heads, root intrusion and pressure drift across a manifold.
Then the designer of record signs Element 2 of Appendix B, certifying that based upon periodic site observations the planting and irrigation conform to the approved package. The local agency approves or denies under section 494(d)(2).
That approval is the last dated institutional act in the record.
So every landscape built to MWELO falls outside it. Plant factors are fixed on the worksheet the day it is drawn, and nothing in the chapter provides a way to revisit them, so the worksheet keeps describing a moment the canopy grew out of.
Whether the ordinance regulates the establishment period or only describes it has two honest sides. One reading says regulates: the period is a defined term, section 493.4(a)(2)(A) makes an establishment schedule a mandatory submittal, and a defined object carrying a mandatory deliverable is a regulated object. The other says describes: that submittal is filed on the last day of installation, section 494 closes the applicant's duty at approval, and nothing requires anyone to observe or report across the years the definition covers.
The chapter does not settle who holds the landscape afterward either. Appendix B puts the only forward-looking promise on the project applicant, whom the chapter nowhere requires to still hold an interest in the property, and section 494(c)(2) sends copies to the property owner while section 494(b)(2)(B) puts the hydrozone diagram at the controller, which is the owner's controller in the owner's cabinet. Two roles, one signature, no provision naming which of them answers in year three.
The property manager who inherits it signed nothing.
The revision interval is three years. The establishment period the regulation defines is one year, or two where irrigation stops, and the trees that may need three to five sit on nobody's calendar in between.
Adoption is local, which is the last variable. Government Code section 65595(c)(1) requires a city or county to adopt an ordinance at least as effective as the updated model, or the model itself, and section 65595(d) applies the model where neither happened. A jurisdiction may go stricter, and a stricter budget tightens what the design may allow the established landscape, since section 490.2(a)(50) defines MAWA as the upper limit of annual applied water for that established area. The establishment years sit outside that budget, scheduled separately under section 493.4(a)(2)(A), which is a gap rather than a squeeze.
The one allowance running at ETAF 1.0, the Special Landscape Area under section 490.2(a)(26)(C), is defined by use category, edible plants and recreational and recycled-water areas, not by plant age. Another constraint on palette is being drafted rather than applied: the Zone 0 defensible-space regulation the Board of Forestry and Fire Protection has worked on since 2025 passed its December 31, 2025 statutory deadline unadopted, and stayed that way through an April 17, 2026 subcommittee draft.
None of which reaches the second summer, which is the first summer that tells anybody anything. Year one a planting looks like whatever it was installed as. The failures that matter, girdling roots, chlorosis off a pH nobody amended, a lateral running dry behind a valve never rebalanced after the audit, arrive as thinning canopy first and as removals later, well after the record closed.
By then the designer of record is on other work, the auditor was never coming back, and the counter file closed the week the certificate cleared. Contractors watching filings for landscape work across Southern California read the ground-up jobs first, and those same filings mark, three summers out, the sites where somebody will want an answer about the trees.
The hydrozone diagram is zip-tied inside the controller cabinet where section 494(b)(2)(B) put it, laminated on a good job. Next spring somebody opens that door to change a battery, reads the sheet, and finds a schedule written for a landscape that no longer exists.
The ordinance concedes the timescale in its own definitions and then declines to cover it. Section 490.2(a)(23) fixes the establishment period at the first year after installing the plant, or the first two years if irrigation will be terminated, and adds that most plants are typically established after one or two years while native habitat mitigation areas and trees may need three to five. The defined length is one year, or two. The concession is three to five, and it attaches to exactly the plants a commercial site gets judged on twenty years later.
One year on the page, three to five in the ground, and a single dated approval covering both.
What gets filed before anybody digs
MWELO attaches at 500 square feet of landscape area on new construction under section 491(a)(1), and at 2,500 on a rehabilitated landscape under section 491(a)(2), wherever the work needs a permit or plan check. Between 500 and 2,500 on new construction, section 491.2(b) lets the applicant pick the prescriptive or the performance option, and at 2,500 and above section 491.2(c) takes the choice away. That is where the submittal goes from two documents to six. Section 491.4(a) wants a project information sheet and a landscape design plan; section 491.4(b) wants those two plus a soil management report, a grading plan, an irrigation design plan and the Water Efficient Landscape Worksheet.The worksheet is where planting stops being planting and becomes a budget. MAWA equals ETo times 0.62 times ETAF times regular landscape area plus 1.0 times special landscape area, sections 490.2(a)(26) and 493.3(a)(1) cap ETAF at 0.55 residential and 0.45 non-residential, and ETo comes out of Appendix C, a table of annual inches: Long Beach 45.8, Palm Desert 70.9. A designer of record working both ends of that table knows which plan set gets argued about, and the argument is about palette, the one running underneath the region's turf conversion programs.
The soil management report is the only document in the package describing something with a memory, and section 493.1 wants texture, infiltration rate, pH, salts, sodium and organic matter. Where mass grading is planned it arrives at the end with the certificate, after the thing it sampled is gone. A plan checker approves or denies under section 491.3(b), and the file goes quiet for the length of a construction schedule.
The last day, and three schedules written for a summer the site has not seen
The Certificate of Completion Package under section 494(b) has six elements, two of them promises about time. Section 493.4(a)(2) requires scheduling parameters for three states, the plant establishment period, the established landscape and temporarily irrigated areas, and section 493.4(a)(3) says each schedule shall consider for each station all of the following parameters that apply, among them interval, run times, cycle starts, root depth and distribution uniformity. Consider, and that apply. Section 493.5 adds a maintenance schedule: aerating, topdressing, mulch, pruning, weeding and clearing the emission devices.All three irrigation schedules are written on one day and handed to a controller that has never seen a summer.
The handoff between the establishment schedule and the established-landscape schedule is not a date. Section 490.2(a)(22) defines the established landscape as the stage at which plants have developed significant root growth into the soil, which is a judgment somebody makes by going and looking, and no section requires anybody to go and look.
Section 493.6 sends a certified landscape irrigation auditor out once, and bars that auditor from being the person who designed or installed it, which is a real and well-drawn protection. On multi-installation projects, section 493.6(b) accepts one lot in seven. Under the prescriptive option there is no audit at all, which DWR said plainly in the Final Statement of Reasons for the 2025 rulemaking.
What that one visit measures is largely up to the agency, because section 493.6(c)(1) says the audit report may include, but is not limited to, inspection, system tune-up, system test with distribution uniformity, and reporting overspray or run off. The only inspection the chapter schedules is not required to test uniformity at all.
The 0.65 figure lives elsewhere. Section 493.2.2(e)(4)(B)(1) makes overhead irrigation systems document a low quarter distribution uniformity of 0.65 or higher using the protocol in ASABE/ICC 802-2020, a documentation duty on the emission devices discharged while the heads are plumb and the shrubs that will block them are still ankle high. Uniformity comes apart afterward, on clogged emitters, tilted heads, root intrusion and pressure drift across a manifold.
Then the designer of record signs Element 2 of Appendix B, certifying that based upon periodic site observations the planting and irrigation conform to the approved package. The local agency approves or denies under section 494(d)(2).
That approval is the last dated institutional act in the record.
December 1, 2015, a date that does not move
One provision in the chapter recurs on the ground rather than in a filing cabinet, and it is worth reading for who it leaves out. Section 491.1(a)(1) says a local agency shall administer programs that may include, but not be limited to, irrigation water use analyses, surveys and audits, measured against a Maximum Applied Water Allowance calculated at an ETAF of 0.8. Section 491.1(a)(1)(A) confines those programs to existing non-rehabilitated landscapes over one acre installed before December 1, 2015. DWR wrote a date there instead of an age.So every landscape built to MWELO falls outside it. Plant factors are fixed on the worksheet the day it is drawn, and nothing in the chapter provides a way to revisit them, so the worksheet keeps describing a moment the canopy grew out of.
Whether the ordinance regulates the establishment period or only describes it has two honest sides. One reading says regulates: the period is a defined term, section 493.4(a)(2)(A) makes an establishment schedule a mandatory submittal, and a defined object carrying a mandatory deliverable is a regulated object. The other says describes: that submittal is filed on the last day of installation, section 494 closes the applicant's duty at approval, and nothing requires anyone to observe or report across the years the definition covers.
The chapter does not settle who holds the landscape afterward either. Appendix B puts the only forward-looking promise on the project applicant, whom the chapter nowhere requires to still hold an interest in the property, and section 494(c)(2) sends copies to the property owner while section 494(b)(2)(B) puts the hydrozone diagram at the controller, which is the owner's controller in the owner's cabinet. Two roles, one signature, no provision naming which of them answers in year three.
The property manager who inherits it signed nothing.
Three years between revisions, one year on the definition
Government Code section 65596.5 requires DWR to review the model ordinance at least every three years, and DWR did, in amendments effective January 2, 2025 that repealed sections 492.1 through 492.18 and Appendix D and rebuilt the performance requirements at section 493. A public hearing followed on December 8, 2025, and local agencies report implementation to DWR every January 31 under section 495(a).The revision interval is three years. The establishment period the regulation defines is one year, or two where irrigation stops, and the trees that may need three to five sit on nobody's calendar in between.
Adoption is local, which is the last variable. Government Code section 65595(c)(1) requires a city or county to adopt an ordinance at least as effective as the updated model, or the model itself, and section 65595(d) applies the model where neither happened. A jurisdiction may go stricter, and a stricter budget tightens what the design may allow the established landscape, since section 490.2(a)(50) defines MAWA as the upper limit of annual applied water for that established area. The establishment years sit outside that budget, scheduled separately under section 493.4(a)(2)(A), which is a gap rather than a squeeze.
The one allowance running at ETAF 1.0, the Special Landscape Area under section 490.2(a)(26)(C), is defined by use category, edible plants and recreational and recycled-water areas, not by plant age. Another constraint on palette is being drafted rather than applied: the Zone 0 defensible-space regulation the Board of Forestry and Fire Protection has worked on since 2025 passed its December 31, 2025 statutory deadline unadopted, and stayed that way through an April 17, 2026 subcommittee draft.
None of which reaches the second summer, which is the first summer that tells anybody anything. Year one a planting looks like whatever it was installed as. The failures that matter, girdling roots, chlorosis off a pH nobody amended, a lateral running dry behind a valve never rebalanced after the audit, arrive as thinning canopy first and as removals later, well after the record closed.
By then the designer of record is on other work, the auditor was never coming back, and the counter file closed the week the certificate cleared. Contractors watching filings for landscape work across Southern California read the ground-up jobs first, and those same filings mark, three summers out, the sites where somebody will want an answer about the trees.
The hydrozone diagram is zip-tied inside the controller cabinet where section 494(b)(2)(B) put it, laminated on a good job. Next spring somebody opens that door to change a battery, reads the sheet, and finds a schedule written for a landscape that no longer exists.