The issue of how to manage stormwater for wineries likely brings to mind irrigation and drainage management.

A large number of wineries, however, must comply with California’s General Permit for Stormwater Discharges Associated with Industrial Activities. Wineries that currently operate under the General Stormwater Permit should be aware that the State Water Board recently published a long-awaited revision to the permit that could have a significant impact on their operations and costs.

The current General Stormwater Permit imposes many requirements on facilities. First, a facility must develop and implement a Stormwater Pollution Prevention Plan ("SWPPP"). Second, the facility must monitor stormwater discharges during the rainy season. Third, the facility must submit an annual report that contains a self-evaluation of the facility’s compliance and the monitoring results. These general obligations would remain under the draft General Stormwater Permit, but would be made substantially more stringent.

The SWPPP is the heart of the General Stormwater Permit. It is a facility-specific compliance plan that identifies the sources of pollution at the facility that could affect stormwater, and describes the best management practices ("BMPs") that the facility will implement to reduce or prevent stormwater from contacting pollutants at the facility. For most wineries, the number of potential stormwater pollutants is small, and the BMPs are relatively straightforward.

The draft General Stormwater Permit would add more meat to the SWPPP by requiring a set of specific minimum BMPs. Most wineries will likely find that the BMPs in their existing SWPPP already meet the draft’s requirements, although some facilities will need to revise their SWPPPs to comply. In addition, the draft General Stormwater Permit would ratchet up the need for technical expertise. The SWPPP would have to be prepared by a “qualified stormwater professional” who must be a registered engineer, geologist, landscape designer or hydrogeologist, and has been certified by the State Board in stormwater control.

That means hiring a consultant with those credentials, unless the facility has that expertise in-house. Facility personnel that implement the SWPPP are also required to be trained in stormwater management, but would not need advanced degrees.

Under the current General Stormwater Permit, a facility must perform visual monitoring of stormwater discharges and take stormwater samples during two qualifying storm events during the wet season.

Many wineries currently take advantage of an option for reduced monitoring burdens in the current General Permit by participating in a group monitoring program, the California Wineries Monitoring Group. Under this program, participating wineries only need to take two samples every five years. However, the draft General Permit is silent on the group monitoring option, raising the possibility that group monitoring would not be allowed, and ratchets up the standard monitoring requirements further, including a significant increase in the number of inspections.

Perhaps the most fundamental requirement in the current General Stormwater Permit is that the stormwater discharge from a facility must not cause a violation of the state’s water quality standard. Under the current permit, this is a “narrative” prohibition, in that the permit does not specify numeric limits on particular pollutants found in facility’s stormwater discharge.

The draft General Stormwater Permit would maintain the narrative prohibition, but would dramatically change how a facility evaluates whether its SWPPP is adequate by establishing Numeric Action Levels (NALs) for specific pollutants. One of the biggest and most controversial changes would be a new requirement that dischargers sample stormwater discharge and analyze for pH, total suspended solids, conductivity, and oil and grease, with sample results then compared to Numerical Action Limits. Exceeding a NAL would require the discharger to take certain corrective actions.

The public comment period on the draft General Permit closed on April 29. Comments at a recent State Water Board hearing on the draft permit reflected concern that the State Board was moving too quickly on such an important regulation and expressed concern about increased compliance burdens. In fact, in an unusual occurrence, two elected officials, Sen. Rod Wright, D-Inglewood, and Rep. Jeff Miller, R-Corona, made comments at the hearing focusing on these two points. The Water Board has said that there will be another opportunity for comment after it issues a revised draft of the permit addressing the current round of comments.

Overall, for wineries and other businesses that are subject to the current General Stormwater Permit, the adoption of a new General Stormwater Permit has the potential to substantially impact operations and compliance costs. The actual impact depends on what revisions the State Board makes to the current draft, as well as facility-specific factors. Businesses that are subject to the current General Stormwater Permit should keep an eye out for the next draft, which is due out later this year, and review it closely to assess the potential impacts to their operations and gauge whether to participate in the ongoing regulatory process.