Overview
Limits specify wastewater discharge monitoring requirements and effluent limits for a permit. Before limits can be added, a permit must include at least one feature. Limit sets and limits are then added to those features. Limit sets and limits drive the generation of Discharge Monitoring Reports (DMR), which permittees must submit as a condition of their permit.
Limit sets and limits can only be modified when a permit is in In Process status. Once a permit status is changed to Issued/In Effect, DMRs are generated based on the entered limit sets and limits. At that point, limits can no longer be edited.
If the Limits tab does not appear on a permit, it may need to be configured in the Permit Categories lookup under the Permit Feature Display Mode setting.
If the Limits tab does not appear on a permit, it may need to be configured in the Permit Categories lookup under the Permit Feature Display Mode setting.
Limit Sets
Limit sets define the time period DMRs cover and the date that DMRs begin for a permit. A limit set can relate to multiple permit features, which can be helpful when defining limits for permits that contain a large number of outfalls. Each limit set contains one or more monitoring requirements or effluent limits. For example, a limit set may indicate that the permittee must submit a monthly report containing sampling data for outfall 001.
Limit sets are typically used to group sampling requirements based on monitoring frequency at an outfall, but can also be used to group limits that must be reported under different operating conditions. For example, a facility may have two different sets of effluent limits at an outfall based on data that varies month to month, such as factory production output or receiving stream flow. In a case like this, with tiered limits, a limit set can be established to represent each condition. The permittee can then complete the DMR for the limit set that applied for that period and report “No Discharge” for the limit set that did not apply.
Adding and Editing Limit Sets
Limit sets and limits can only be added, modified, or deleted if the permit is in In Process status and the user has permissions to edit the permit. Limit sets may also be deleted if they are associated with a prior permit version.
On the Limits tab of the Permit Details page, the following actions may be taken:
Click the Add Limit Set button to add a new limit set.
Click the Copy Limit Set button to copy a limit set from a limit set template or to copy a limit from another permit.
Click the Open button to view or edit an existing limit set.
Click the Copy button to copy a limit set as a new limit.
Fixing Initial Monitoring Dates
A Fix Initial Monitoring Dates button appears if any of the following issues exist:
A limit set is missing an initial monitoring date.
The initial monitoring date entered for a limit set would create DMRs for monitoring periods before the current permit version’s effective date.
A limit set’s reporting period is not monthly and does not begin in the expected calendar month. (This validation is only performed if nVIRO is configured to do so.)
Clicking this button automatically calculates a valid limit set’s initial monitoring dates. Since situations can vary, make sure to verify that the calculated dates are correct for the given permit.
Limit Set Controls
When adding or editing a limit set, the following fields are displayed:
Field | Description | Notes |
|---|---|---|
Limit Set Name | A short text description of the limit set. | This is displayed on the top of a DMR form to help identify the limit set. |
Limit Set Description | A long text description of the limit set. | This is displayed on the internal Limit Set page to help internal users better understand the purpose of the limit set. |
ICIS Limit Set Designator | A one- or two-character identifier used to identify the limit set on the permit feature. | This value is suffixed onto the Permit Feature Identifier for display in lists and on DMR data entry pages. For example, designator “A” on permitted feature “001” would display as limit set “001A.” |
Limit Set Status | The current status of the limit set (Pending, Active, or Closed). | Limit sets default to Active status when created, and the Status Date is synchronized with the initial monitoring date. If a limit set is in Pending status, DMRs will not be created for this limit set when the permit is issued. If the limit set status needs to be changed after a permit is put into effect, the permit will need to be returned to In Process status. Statuses cannot be edited once they have been flowed to ICIS-NPDES. |
Wastewater Types | A drop-down list of wastewater types. | Only wastewater types assigned to the permit feature associated with the limit set can be selected. The list will not display if no wastewater types have been configured in the system. These values can be configured to be sent to ICIS-NPDES as Permitted Feature Characteristics. This field has no bearing on the creation of DMRs. |
Design Flow or Authorized Flow / Unit | The amount of flow that the wastewater system is designed to process or that is authorized for this limit set. | This field has no bearing on the creation of DMRs. |
Conveyance | A text description of how the wastewater is conveyed to the receiving stream (for example, “unnamed ditch”). | This field is used in permit document templates to construct a sentence describing how the wastewater reaches a receiving stream. |
Generate DMRs | A checkbox that indicates whether to generate DMRs for this limit set. | If the facility is allowed to perform retained self-monitoring, clear this box. When cleared, the limit set and associated limits will not flow to ICIS-NPDES. |
Scheduled | A checkbox that indicates whether the DMR is scheduled or unscheduled. | Most limit sets are scheduled, meaning that DMRs should be generated at a regular, predictable frequency. Unscheduled limit sets are for event-based DMR reporting that occurs unpredictably (for example, a bypass caused by a rain event). If one or more unscheduled limit sets exist on a permit, users will have the option to submit an unscheduled DMR on the DMR List page. When selected, the user is prompted to select from a list of available unscheduled limit sets. |
Monitoring Period | The time period covered by each generated DMR form. | |
Reporting Period | The frequency at which DMRs must be submitted. | The selected frequency must be less than or equal to the monitoring period and be equally divisible by the monitoring period. It is recommended that the reporting period match the monitoring period. Varying reporting periods was useful when DMRs were completed on paper, as it simplified mailing requirements for permittees. With electronic reporting, this flexibility is less relevant. |
First DMR Begin Date | The start date of the earliest DMR in the limit set. | For non-monthly limit sets, this date determines the cadence for all future DMR periods. For example, if the First DMR Begin Date for a limit set with quarterly monitoring is in February, the generated DMRs will be in February, May, August, and November each year. If quarterly DMRs should fall on regular calendar quarters, the First DMR Begin Date must be in January, April, July, or October. This is true even if the limits in the limit set do not start in one of these months. |
Days from Report End Date When Due | The grace period between the end of a DMR monitoring period and the DMR due date. For example, if a DMR is due 15 days after the end of each monitoring period, then 15 should be entered. | DMRs will show as late if the due date passes. nVIRO can be configured to not calculate late DMR violations for a defined period after the due date. For agencies that still receive paper reports, this can provide a buffer to complete data entry before late violations are generated. |
Applicable Months | The months to which limits within the limit set apply. | As a convenience feature, the selected months serve as the default applicable months when new limits are added to the limit set. Applicable months can always be manually changed on each limit. |
Special Instructions | Instructions that are displayed on the DMR data entry form. | This should be used to describe any limits for which a “See Comments” monitoring location has been added or to provide instructions to external users about how to complete the DMR. |
Limits
Limits include monitoring requirements and effluent limits. Limits are added to a limit set and define the parameters that display on DMR forms. Each limit consists of a parameter (substance or condition to be measured), a monitoring location (where the sample should be taken, or another special condition), and one or more limit values.
The standard EPA DMR summary form defines up to five limits for a given parameter, grouped by quantity and concentration. The five-column format offers a compact way to present the data entry interface, whether on paper or electronically. A parameter needs only one limit entered in any of the five columns to be saved.
Adding and Editing Limits
On the Limits tab, the following actions may be taken:
Click the Add Limit button to add a new limit.
Click the Open button to view or edit an existing limit.
Click the Copy button to copy an existing limit as a new limit.
Basic Limit Controls
When adding or editing a limit, the following fields are displayed:
Field | Description | Notes |
|---|---|---|
Limit Set | The limit set to which the limit relates. | |
Parameter | The substance or condition to be measured. | |
Monitoring Location (Stage) | The location from which the sample should be taken (for example, final effluent, influent, upstream, or downstream). | The monitoring location can also be used to segment conditions when different limits apply to the same parameter. For example, any of the “See Comments” options can be used in this scenario. |
Zero values allowed on DMR entry | A read-only label that indicates whether zero values can be entered in a DMR for the selected parameter. | This value can be changed by an administrator on the nVIRO Parameter Lookup Maintenance page. |
Modification Number | A read-only field used for migrated data where limit modifications were performed. | nVIRO does not support limit modifications; a new permit version must be created to change monitoring requirements or limits. |
Start Date | The date on which sampling for the parameter begins. | Select the Use Permit Effective Date box if monitoring is to begin when the permit becomes effective. |
End Date | The date on which sampling for the parameter ends. | Leave this field blank if monitoring is to continue for the life of the permit, even if the permit expires or is administratively continued. If the end date is entered and matches the permit expiration date, it will also continue after the permit expires as long as the permit version is active. |
Applicable Months | The months to which the parameter applies. | If a limit varies seasonally, two limits can be entered—one for the summer months and one for the winter months. Care should be taken to avoid overlapping seasonal limits within the same limit set period. This is only of concern for non-monthly limit sets. For example, if a temperature limit for summer applies from May–August and a winter limit applies to all other months, but a quarterly DMR covers August–October, the limit will appear twice on the DMR with different season numbers. Permittees may require special instructions on how to report this condition when it occurs. |
Quantity/Loading Area | Monitoring requirements and effluent limits for mass. |
Limits and Monitoring Requirements Controls
The Limits and Monitoring Requirements area displays the quantity and concentration monitoring requirements and effluent limits. The data entry controls are arranged in a five-column grid that allows up to two quantities and three concentrations.
The example below shows a typical limit for pH, where the DMR reported value must be greater than 6 and less than 9 standard units (SU).
The following fields are displayed in this area:
Field | Description | Notes |
|---|---|---|
Limit Type | Classification of the limit into one of three types: Optional Monitoring: Allows for optional reporting of measurements. No violation is created if left blank on a DMR. Required Monitoring: Requires that a value be reported but does not specify minimum or maximum thresholds. A violation is created if not reported on a DMR. Limit: Enforces a minimum or maximum threshold. Data entry is required on the DMR, and a violation is created if the threshold is exceeded. | |
Limit Value Qualifier | The minimum or maximum threshold for the calculation of violations. | This field is displayed when the Limit Type is Limit. When this field is left blank, value exceedance calculations are based on the selected statistical base:
Value qualifiers, if specified, should align with the comparison direction defined by the statistical base. For example, average and maximum statistical bases should use < or ≤, whereas minimum statistical bases should use > or ≥. In other words, the qualifier determines the conditions under which a DMR value is considered a non-violation. |
Statistical Base | For DMR summary reporting, this field specifies the type of aggregation formula to use when reporting minimums, averages, and maximums for the limit over a DMR reporting period. | |
Basis | The basis for the limit. | Not required. Selection has no bearing on DMR generation or calculation logic. |
… | Comments related to the limit. | Not required. Comments entered here are not displayed on a DMR. |
Quantity Unit | The unit of measure for quantity or loading limits. | Only units that apply to the selected parameter are displayed. |
Quality/Concentration Area | Monitoring requirements and effluent limits for concentrations (for example, measurements in milligrams per liter). | |
Concentration Unit | The unit of measure for quality or concentration limits. | Only units that apply to the selected parameter are displayed. |
Sample Frequency | The frequency at which samples are to be taken. | Displayed on the DMR form. |
Sample Type | The type of sample to be taken. | Displayed on the DMR form. |
Bulk Updating Limit Details
The following limit-related fields can be updated in bulk on a draft permit:
Monitoring Location
Limit Start Date
Use Permit Effective Date
Limit End Date
Sample Frequency
Sample Type
Months
Is Enforceable
Note that limit values cannot be bulk updated.
To bulk update multiple limits:
Select one or more limits from the list of limit parameters.
Click the Bulk Update button to open the bulk update modal.
Select fields to bulk update and update the fields accordingly.
Click the Save button. The limits are updated to reflect the changes.
Limit Summary and Detail View Modes
By default, the limit list appears in summary mode, which outlines key information such as limit set, parameters, monitoring location or stage, and applicable months. To support online review of permit limits, the list may also be viewed in detail mode, which includes additional fields, such as frequency, statistical base, DMR col (quantity/concentration) value, and units.
To toggle between Summary and Detail modes, click the View As: Summary | Detail button at the top of the limit list.
Creating DMRs upon Permit Issuance
DMRs are created when a permit’s status changes to In Effect. This can happen either when a user manually changes a permit status from In Process to Issued/In Effect on or after the permit effective date, or as part of an automatic process that updates permit statuses from Issued (Not in Effect) to In Effect on their respective effective dates.
When updating a permit status from In Process to Issued/In Effect, a series of validation messages appear to verify that the limit set and limit data have been entered correctly.
If a permit with limits is in effect, a View DMRs button appears in the Other Actions section of the right sidebar on the Permit Details page. Clicking this button opens the DMR List page—the same page that external users use to fill out DMRs.
To see how many DMRs were created when the permit was issued, click the Audit History button on the Permit Details page. If the permit version is a modification of an existing permit, unsubmitted and draft DMRs on the superseded permit version are removed and recreated using the updated limit set and limit definitions. If DMRs were replaced, this information is also visible in the permit’s audit history.
In some cases, this can leave what appear to be duplicate DMRs for the same reporting period, each with data from the previous and current permit versions. This can occur in two scenarios:
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DMRs are created through the permit’s expiration date. Once a permit expires, it transitions to either Extended or Expired status. The system continues to create DMRs for six months after permit expiration, however, this period can be shortened or extended by an administrator.