Stormwater Management: Ontario vs Rialto
How do stormwater management rules compare between Ontario, CA and Rialto, CA?
Ontario and Rialto have similar restriction levels.
Ontario, CA
San Bernardino County
Ontario enforces the Santa Ana Regional MS4 permit requiring erosion control, trash capture, and Low Impact Development for projects over 5,000 square feet, with enforcement through OMC Chapter 5 Article VI.
View full Ontario rules →Rialto, CA
San Bernardino County
Rialto is a co-permittee on the San Bernardino County MS4 NPDES Permit issued by the Santa Ana Regional Water Quality Control Board (Order R8-2010-0036, NPDES No. CAS618036) and enforces stormwater quality controls under Title 13 (Public Services) of the Municipal Code. All non-stormwater discharges to the storm drain (including wash water, paint, oil, and sediment) are prohibited, and construction sites ≥1 acre require coverage under the Statewide Construction General Permit and a SWPPP.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| Permit | Santa Ana Regional MS4 | - |
| Code | OMC Ch 5 Art VI | - |
| CGP threshold | 1 acre disturbance | - |
| LID threshold | 5,000 sq ft impervious | - |
| MS4 Permit | - | Santa Ana Region Order R8-2010-0036, NPDES CAS618036 |
| Construction permit threshold | - | ≥1 acre disturbed (Construction General Permit) |
| Local code | - | Rialto Municipal Code Title 13 - Public Services |
| Priority concern | - | Perchlorate plume - heightened source control |
| State authority | - | Cal. Water Code §§13260, 13385 |
Highlighted rows indicate differences between cities.
Ontario FAQ
Can I wash my driveway down the street?
No, wash water is a prohibited non-stormwater discharge; dry sweep first and capture any wash water for disposal.
Do I need a SWPPP for a home addition?
Only if the addition disturbs 1 acre or more of soil; smaller projects follow local erosion-control Best Management Practices.
Rialto FAQ
Do I need a permit to wash my driveway in Rialto?
Wash water cannot discharge to the storm drain. Use dry methods (sweeping) or capture and dispose of wash water to the sanitary sewer with permission. Untreated discharge of soap, oil, or sediment to the gutter is an illicit discharge under Title 13.
When do I need a SWPPP for construction?
Any project disturbing 1 acre or more (including smaller sites that are part of a larger common plan) must obtain coverage under the State Construction General Permit and maintain a SWPPP. Smaller sites in Rialto still need erosion and sediment BMPs under the city WQMP.
Can I drain my pool to the street?
Only if dechlorinated and pH-neutral, and only with prior approval. Generally Rialto requires pool water to be discharged to the sanitary sewer via an approved cleanout.
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