# Consolidation candidate screening — California water systems

URL: https://municorn.us/consolidation/california-water-systems/

> **Cite as:** Municorn.us, "Consolidation candidate screening — California water systems", Municorn water loss index, https://municorn.us/consolidation/california-water-systems/ (source filings retrieved 2026-09-12).
> **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/ — reuse and redistribution are permitted with attribution to Municorn.us and a link to this URL.
> **Caveat that must travel with these figures:** "Water loss" is at least three different quantities depending on the jurisdiction, and nothing here supports a comparison between states.

Which California water systems border which, from EPA's own service area boundary layer, and what the
published figures say across each border. **A screen, not a recommendation**: nothing here says two utilities
should merge and nothing here is a feasibility result.

## What "bordering" means

Two systems are listed as bordering when their service area outlines come within **1.11 km**
of each other. That is a proximity test and not a touch test, because the boundary layer is simplified by about
a kilometre at acquisition and simplification moves vertices — an exact touch test on these bytes would be a
question about our own simplification rather than about the world. It is not a statement that two systems share
a pipe or an interconnection: nothing in this corpus knows about pipes.

## How EPA got these shapes

| Boundary basis | Systems | With a neighbour | Mean neighbours |
|---|---:|---:|---:|
| published | 581 | 527 (91%) | 5.08 |
| modelled | 2 | 1 (50%) | 0.5 |
| unstated | 2 | 2 (100%) | 16.5 |



## The pairs

2145 bordering pairs. Ordered by how many times larger one side is than the other, and by nothing else — a composite score over size, loss and compliance would be a judgement about how much one is worth against another, and this corpus has none to offer.

**Computed over EPA's whole national layer, before any filter to this site.** 2145 borders reach
this state's drawn systems: 1303 of them name a system this site publishes no page for, and 45
cross a state line. Until #180 neither kind existed here, because the borders were computed on the map's own
per-state, corpus-filtered extract. A row with an unknown side carries EPA's name for it, its primacy agency
and how EPA got its boundary, and nothing else — no loss, no size, no rates — and it sorts below every row
this site can describe.

**A cross-state pair may not have its loss figures compared, and this page does not compare them.** Crossing a
state line means crossing a primacy agency, and "water loss" is at least three different quantities across the
regulators in this corpus. The loss gap on such a row reads "not comparable", which is a statement about the
two regulators rather than about the two utilities.

| Primacy agency | Endpoints on a cross-state edge | Modelled |
|---|---:|---:|
| CA | 45 | 0 (0%) |
| 9 | 40 | 40 (100%) |
| IL | 2 | 0 (0%) |
| NV | 2 | 2 (100%) |
| AZ | 1 | 0 (0%) |

The modelled share is a fact about each state rather than a national average, so an edge basis is doing more
work on a cross-state row than on any other: its two endpoints are drawn from two different modelled
populations.


| The larger | People | Loss | The smaller | People | Loss | Size ratio | Loss gap | Together | Edge |
|---|---:|---:|---|---:|---:|---:|---:|---:|---|
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Scv Water-regional | 26 | 1.4% | 149,060× | 7.2 pp | 3,875,592 | one modelled |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Vernon Public | 200 | 5.4% | 19,378× | 3.2 pp | 3,875,766 | both published |
| Santa Clarita Valley Water Agency | 282,784 | 6.8% | Scv Water-regional | 26 | 1.4% | 10,876× | 5.4 pp | 282,810 | one modelled |
| Scv Water - Santa Clarita | 135,281 | 12.9% | Scv Water-regional | 26 | 1.4% | 5,203× | 11.5 pp | 135,307 | one modelled |
| Ventura County Water Works District 8 | 125,778 | 6.3% | Scv Water-regional | 26 | 1.4% | 4,838× | 4.8 pp | 125,804 | one modelled |
| Eastern Municipal Water District | 666,581 | 7.3% | Wmwd - Rainbow | 190 | 35.7% | 3,508× | 28.4 pp | 666,771 | both published |
| Santa Rosa | 178,127 | 5.4% | Cws Rdv Hawkins | 81 | 20.0% | 2,199× | 14.7 pp | 178,208 | both published |
| Roseville | 155,612 | 9.6% | Placer County Water Agency Bianchi | 98 | 4.2% | 1,588× | 5.5 pp | 155,710 † | both published |
| Victorville | 135,000 | 5.0% | Apple Valley Ranchos Water - Bellview | 98 | 17.1% | 1,378× | 12 pp | 135,098 | both published |
| Modesto Main | 233,308 | 5.8% | Modesto - Ceres | 175 | 10.4% | 1,333× | 4.6 pp | 233,483 | both published |
| Eastern Municipal Water District | 666,581 | 7.3% | Lake Hemet MWD Garner Valley | 709 (EPA) | 10.1% | 940.2× | 2.8 pp | 667,290 | both published |
| Rancho California Water District | 155,000 | 6.1% | Wmwd - Rainbow | 190 | 35.7% | 815.8× | 29.6 pp | 155,190 | both published |
| Cws Ela East Los Angeles | 152,474 | 5.4% | Vernon Public | 200 | 5.4% | 762.4× | 0.1 pp | 152,674 | both published |
| Sacramento Department Of | 520,407 | 4.8% | Sacramento County Water Agency - Southwest Tract | 759 | 13.3% | 685.6× | 8.5 pp | 521,166 † | both published |
| Scv Water - Newhall | 17,498 | 7.6% | Scv Water-regional | 26 | 1.4% | 673× | 6.2 pp | 17,524 | one modelled |
| Apple Valley Ranchos | 63,514 | 9.8% | Apple Valley Ranchos Water - Bellview | 98 | 17.1% | 648.1× | 7.2 pp | 63,612 | both published |
| Scv Water - Pinetree | 15,998 | 12.6% | Scv Water-regional | 26 | 1.4% | 615.3× | 11.2 pp | 16,024 | one modelled |
| Turlock | 72,682 | 18.1% | Modesto - C Turlock | 119 | 1.2% | 610.8× | 16.9 pp | 72,801 | both published |
| Truckee Donner Public Utility District | 31,383 | 24.5% | Tdpud Hirschdale | 61 | 8.4% | 514.5× | 16.2 pp | 31,444 | both published |
| Fresno | 568,964 | 8.6% | Bakman Water - Rolling Hills | 1,106 | 9.0% | 514.4× | 0.4 pp | 570,070 † | both published |
| East Bay Municipal Utility District | 1,400,000 | 9.1% | Vallejo - Main | 2,800 | 22.0% | 500× | 12.9 pp | 1,402,800 † | both published |
| East Bay Municipal Utility District | 1,400,000 | 9.1% | Vallejo - Lakes | 2,800 | 44.4% | 500× | 35.3 pp | 1,402,800 † | both published |
| Turlock | 72,682 | 18.1% | Modesto - N Turlock | 172 | 11.8% | 422.6× | 6.3 pp | 72,854 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Scv Water - Castaic | 9,999 | 11.1% | 387.6× | 2.5 pp | 3,885,565 | both published |
| Scv Water - Castaic | 9,999 | 11.1% | Scv Water-regional | 26 | 1.4% | 384.6× | 9.7 pp | 10,025 | one modelled |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Gswc - Willowbrook | 10,747 | 4.9% | 360.6× | 3.8 pp | 3,886,313 | both published |
| Gswc - Florence/graham | 63,500 | 7.4% | Vernon Public | 200 | 5.4% | 317.5× | 2.1 pp | 63,700 | both published |
| Ceres | 54,513 | 10.4% | Modesto - Ceres | 175 | 10.4% | 311.5× | 0.1 pp | 54,688 | both published |
| Gswc - Bell Bell Gardens | 54,877 | 6.7% | Vernon Public | 200 | 5.4% | 274.4× | 1.3 pp | 55,077 | both published |
| San Diego | 1,400,000 | 7.6% | Rincon Del Diablo Municipal Water District | 5,105 | 9.5% | 274.2× | 2 pp | 1,405,105 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Huntington Park-city | 15,437 | 7.7% | 251.1× | 0.9 pp | 3,891,003 | both published |
| Scv Water - Tesoro | 6,499 | 38.0% | Scv Water-regional | 26 | 1.4% | 250× | 36.6 pp | 6,525 | one modelled |
| Lac Waterworks District 40, Region 4 & 34 | 208,129 | 4.9% | Cws Av Leona Valley | 878 | 18.2% | 237× | 13.3 pp | 209,007 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | El Segundo | 17,200 | 0.5% | 225.3× | 8.1 pp | 3,892,766 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Scv Water - Newhall | 17,498 | 7.6% | 221.5× | 1 pp | 3,893,064 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Lomita | 20,256 | 7.5% | 191.3× | 1.2 pp | 3,895,822 | both published |
| Desert Water Agency | 75,523 | 9.0% | Mission Springs Water District | 399 (EPA) | 22.0% | 189.3× | 12.9 pp | 75,922 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | California - American Water Company - Los Angeles District - Baldwin Hills | 20,724 | 8.8% | 187× | 0.2 pp | 3,896,290 † | both published |
| Galt | 25,767 | 11.7% | Cws Vis Mullen | 138 | 25.7% | 186.7× | 14 pp | 25,905 † | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Los Angeles County Waterworks District 29 | 22,300 | 4.3% | 173.8× | 4.3 pp | 3,897,866 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | South Pasadena | 25,329 (EPA) | 7.8% | 153× | 0.8 pp | 3,900,895 | both published |
| Lac Waterworks District 40, Region 4 & 34 | 208,129 | 4.9% | Cws Av Lancaster | 1,387 | 11.9% | 150.1× | 7 pp | 209,516 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Liberty Utilities (park Water) | 26,371 | 5.8% | 147× | 2.9 pp | 3,901,937 | both published |
| San Diego County | 3,300,000 | 0.3% | Rainbow Municipal Water District | 23,500 | 8.5% | 140.4× | 8.2 pp | 3,323,500 † | one modelled |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | San Fernando | 28,000 | 4.1% | 138.4× | 4.5 pp | 3,903,566 | both published |
| Oxnard | 232,979 | 7.1% | California - American Water Company - Rio Plaza (el Rio) | 1,709 | 9.2% | 136.3× | 2.2 pp | 234,688 | both published |
| Sacramento Department Of | 520,407 | 4.8% | California - American Water Company - Sacramento District - Arden | 4,191 | 7.0% | 124.2× | 2.2 pp | 524,598 † | both published |
| Rainbow Municipal Water District | 23,500 | 8.5% | Wmwd - Rainbow | 190 | 35.7% | 123.7× | 27.1 pp | 23,690 | both published |
| Suburban | 168,843 | 4.2% | Suburban | 1,437 | 2.8% | 117.5× | 1.4 pp | 170,280 | both published |
| Mission Springs Water District | 43,484 (EPA) | 13.4% | Mission Springs Water District | 399 (EPA) | 22.0% | 109× | 8.6 pp | 43,883 | both published |
| Pasadena | 170,950 | 7.7% | Liberty Utilities (park Water) | 1,619 | 4.7% | 105.6× | 3 pp | 172,569 | both published |
| California - American Water Company - Sacramento District - West Placer | 8,861 | 2.2% | Placer County Water Agency Bianchi | 98 | 4.2% | 90.4× | 2 pp | 8,959 | both published |
| Pleasanton | 75,960 | 10.4% | Sunol - Sfpuc | 847 | 36.4% | 89.7× | 26.1 pp | 76,807 | both published |
| Los Angeles Department Of Water And Power | 3,875,566 | 8.6% | Cws Haw Hawthorne | 44,718 | 6.4% | 86.7× | 2.3 pp | 3,920,284 | both published |
| Mission Springs Water District | 43,484 (EPA) | 13.4% | Mission Springs Water District | 517 (EPA) | 17.2% | 84.1× | 3.8 pp | 44,001 | both published |
| California - American Water Company - Monterey District - Main | 92,450 | 8.0% | California - American Water Company - Monterey District - Hidden Hills | 1,106 | 15.0% | 83.6× | 7.1 pp | 93,556 | both published |
| Huntington Park-city | 15,437 | 7.7% | Vernon Public | 200 | 5.4% | 77.2× | 2.4 pp | 15,637 | both published |
| Sweetwater Springs Water District | 6,000 | 23.2% | Cws Rdv Noel Heights | 79 | 20.0% | 75.9× | 3.2 pp | 6,079 † | both published |
| Contra Costa Water District | 208,528 | 14.2% | Vallejo - Main | 2,800 | 22.0% | 74.5× | 7.8 pp | 211,328 | both published |
| Contra Costa Water District | 208,528 | 14.2% | Vallejo - Lakes | 2,800 | 44.4% | 74.5× | 30.2 pp | 211,328 | both published |


**Two publishers on these rows.** The loss percentage is DWR's own filing. A
population marked (EPA) is not: it is `POPULATION_SERVED_COUNT` from EPA's national inventory of community
water systems, carried on the rows where DWR published no population of its own — it files one for other systems in this table and not for these. **DWR did not publish the figures marked (EPA).** What EPA publishes is the
count a system reports to its primacy agency — not a census, not audited, and the retail population for some
systems and the total population served for others — collected in a different year and for a different purpose
than the loss figure beside it.

† EPA records at least one side of this pair as selling water wholesale to other systems. Two service
populations add only where neither system already serves the other, and nothing in this corpus knows who sells
to whom, so a flagged combined figure is an upper bound rather than a sum.

## Borders to systems this site has no page for

**1303 of these 2145 borders** reach a system this site publishes nothing about. They are
listed separately because the ordering above ranks candidates and a row with one unknown side cannot be ranked
— not because the border is less real. EPA drew both shapes; this corpus holds a filing for one of them. Every
cell about the other side is absent on purpose: this site does not know that system's water loss, its size, its
rates or its compliance record.

| System with a filing here | Its loss | The bordering system | Regulated by | Its boundary | Edge |
|---|---:|---|---|---|---|
| Alameda County Water District | 5.3% | ZONE 7 WATER AGENCY | CA | unstated | one modelled |
| Alameda County Water District | 5.3% | SANTA CLARA VALLEY WATER DISTRICT | CA | unstated | one modelled |
| Amador Water Agency - Buckhorn | 26.4% | FOREST POINT MHC | CA | published | both published |
| Amador Water Agency - Buckhorn | 26.4% | PINE GROVE COMM SERV DIST | CA | published | both published |
| Amador Water Agency - Buckhorn | 26.4% | FIRST MACE MEADOW # 1 | CA | published | both published |
| Amador Water Agency - Buckhorn | 26.4% | FIRST MACE MEADOWS UNIT NO. 2 | CA | published | both published |
| Amador Water Agency - Buckhorn | 26.4% | CALAVERAS PUD | CA | published | both published |
| Amador Water Agency - Tanner | 24.3% | CITY OF JACKSON | CA | published | both published |
| Amador Water Agency - Tanner | 24.3% | PINE GROVE COMM SERV DIST | CA | published | both published |
| Amador Water Agency - Tanner | 24.3% | CALAVERAS PUD | CA | published | both published |
| Amador Water Agnecy - Lk Camanche | 25.0% | CAMANCHE NORTH SHORE INC. | CA | published | both published |
| American Canyon | 9.8% | MEYERS WATER CO. | CA | published | both published |
| American Canyon | 9.8% | NAPA RIVER RANCH | CA | published | both published |
| American Canyon | 9.8% | MILTON ROAD WATER COMPANY | CA | published | both published |
| Anaheim Public | 5.1% | PAGE AVENUE MUTUAL WATER COMPANY | CA | published | both published |
| Anaheim Public | 5.1% | SERRANO WATER DISTRICT | CA | published | both published |
| Anderson | 14.0% | CANYON CREEK MHP | CA | published | both published |
| Anderson | 14.0% | ANDERSON MOBILE HOME PARK | CA | published | both published |
| Anderson | 14.0% | SUNRISE MOBILEHOME PARK | CA | published | both published |
| Anderson | 14.0% | EL RIO ESTATES | CA | published | both published |
| Anderson | 14.0% | ANDERSON PARK VILLAGE | CA | published | both published |
| Anderson | 14.0% | SACRAMENTO RIVER RV PARK | CA | published | both published |
| Anderson | 14.0% | TUCKER OAKS EAST WATER DISTRICT | CA | published | both published |
| Anderson | 14.0% | COTTONWOOD WATER DISTRICT | CA | published | both published |
| Antioch | 17.3% | CASA MEDANOS WATER SYSTEM | CA | published | both published |
| Antioch | 17.3% | RANDALL-BOLD WATER TREATMENT PLANT | CA | unstated | one modelled |
| Antioch | 17.3% | CCWD/BRENTWOOD WTP | CA | unstated | one modelled |
| Apple Valley Ranchos | 9.8% | APPLE VALLEY VIEW MWC | CA | published | both published |
| Apple Valley Ranchos | 9.8% | RIVER RANCH MHP | CA | published | both published |
| Apple Valley Ranchos | 9.8% | NAVAJO MWC | CA | published | both published |
| Apple Valley Ranchos | 9.8% | RANCHERITOS MWC | CA | published | both published |
| Apple Valley Ranchos | 9.8% | THUNDERBIRD CWD | CA | published | both published |
| Apple Valley Ranchos | 9.8% | PARADISE MOBILE ESTATES | CA | published | both published |
| Apple Valley Ranchos | 9.8% | APPLE VALLEY VILLAGE MHE | CA | published | both published |
| Apple Valley Ranchos | 9.8% | BEAR VALLEY MHP | CA | published | both published |
| Arcadia | 8.4% | FOOTHILL MUNICIPAL WATER DIST. | CA | unstated | one modelled |
| Arcadia | 8.4% | HEMLOCK MUTUAL WATER CO. | CA | published | both published |
| Arroyo Grande | 6.4% | CANYON CREST MUTUAL BENEFIT WC | CA | published | both published |
| Arroyo Grande | 6.4% | HALCYON WATER SYSTEM | CA | published | both published |
| Arroyo Grande | 6.4% | COUNTRY HILLS ESTATES | CA | published | both published |

## What "together" can and cannot mean

**People and connections add. Prices do not.** A combined rate is not the average of two rates, and a combined
cost of service cannot be computed from two sets of filed figures without the cost allocation neither utility
publishes. That is why there is a combined population column and no combined rate column.

The loss gap is in percentage points between two filed figures for the years each system last filed, which are
not necessarily the same year.

Source: US EPA community water system service area boundaries, retrieved 2026-09-09; adjacency
derived 2026-09-12 at a 1.11 km tolerance. Service populations marked (EPA) from the US EPA SDWIS inventory of active community water systems,
retrieved 2026-09-09 (`data/archive/sdwis-national/2026-09-09-national-cws-spine.jsonl`).