Texas Wastewater Collection System Categories & Required Operator Levels

Texas wastewater collection systems are classified into three categories based on daily average flow. The category determines the minimum operator license level required for collection-system supervision.

The Texas Commission on Environmental Quality, or TCEQ, recognizes both wastewater collection licenses and wastewater treatment licenses for certain collection-system supervisory duties. Operators should understand the relationship between system category, daily average flow, and minimum required license.

Wastewater Collection System Categories

Texas uses three wastewater collection-system categories:

• Category I;
• Category II;
• Category III.

The categories are based primarily on the collection system's daily average flow.

Category I Collection System

A Category I wastewater collection system has a daily average flow of:

less than 100,000 gallons per day

The minimum acceptable operator license is:

• Collection Class I; or
• Wastewater Treatment Class D.

Category II Collection System

A Category II wastewater collection system has a daily average flow of:

100,000 gallons per day to 1.0 million gallons per day

The minimum acceptable operator license is:

• Collection Class II; or
• Wastewater Treatment Class C.

Category III Collection System

A Category III wastewater collection system has a daily average flow of:

greater than 1.0 million gallons per day

The minimum acceptable operator license is:

• Collection Class III; or
• Wastewater Treatment Class B.

Collection Categories and Treatment Facility Categories Are Different

A common exam mistake is confusing collection-system Categories I, II, and III with wastewater treatment facility Categories D, C, B, and A.

The distinction is:

• collection systems use Categories I, II, and III;
• wastewater treatment facilities use Categories D, C, B, and A.

Collection Licenses and Treatment Licenses

Texas allows appropriately licensed wastewater treatment operators to supervise collection-system operations when their treatment license meets the required level.

The equivalent minimum levels are:

• Collection I or Treatment D;
• Collection II or Treatment C;
• Collection III or Treatment B.

Why Treatment Licenses Can Qualify

A wastewater treatment operator license authorizes work involving treatment facilities and can also qualify an operator for certain wastewater collection-system operation and maintenance duties.

The treatment license must still meet the minimum level required for the collection-system category.

Collection License Scope

A wastewater collection operator license primarily applies to wastewater collection-system operation and maintenance.

Collection-system duties can include:

• gravity sewer operation;
• manhole inspection;
• blockage removal;
• lift-station operation;
• pump maintenance;
• force-main operation;
• overflow response;
• infiltration and inflow investigation.

Collection License Does Not Automatically Authorize Treatment Operation

A collection license does not automatically authorize an operator to perform wastewater treatment plant operator duties.

This is an important exam distinction.

Direct Supervision of Collection Crews

TCEQ requires a person engaged in direct supervision of domestic wastewater collection system operation or maintenance crews to hold an appropriate license.

The supervisor can be:

• a licensed wastewater collection system operator; or
• a licensed wastewater treatment plant operator.

Minimum Collection Supervisor Level

At least one collection supervisor must hold a license class:

equal to or higher than the minimum required for the collection-system category.

Higher Licenses Can Satisfy Lower Requirements

A higher license level can satisfy a lower minimum requirement.

For example, a Collection Class III operator can supervise a Category II system even though the minimum is Collection Class II.

Example: Small Collection System

A collection system has an average flow of:

75,000 gpd

This is less than 100,000 gpd.

The system is:

Category I

The minimum operator level is:

• Collection Class I; or
• Wastewater Class D.

Example: 100,000 gpd Collection System

A collection system has an average flow of exactly:

100,000 gpd

This falls into:

Category II

The minimum operator level is:

• Collection Class II; or
• Wastewater Class C.

Example: 500,000 gpd Collection System

500,000 gpd is between 100,000 gpd and 1.0 MGD.

The system is:

Category II

Example: 1.0 MGD Collection System

A system with daily average flow of exactly:

1.0 MGD

falls within:

Category II

because Category III applies when flow is greater than 1.0 MGD.

Example: 1.2 MGD Collection System

A system averaging:

1.2 MGD

is:

Category III

The minimum operator level is:

• Collection Class III; or
• Wastewater Class B.

Gallons per Day and MGD

Operators should be comfortable converting between gallons per day and MGD.

1.0 MGD = 1,000,000 gallons per day

0.10 MGD = 100,000 gallons per day

Example Conversion

A collection system averages 650,000 gallons per day.

Convert to MGD:

650,000 ÷ 1,000,000 = 0.65 MGD

0.65 MGD is Category II.

Daily Average Flow

The collection-system classification uses daily average flow.

Operators should not classify the system based only on:

• one unusually high-flow day;
• one low-flow day;
• instantaneous pump rate.

Flow Can Change Over Time

Collection systems can grow as customers and service areas increase.

A system approaching a category threshold should monitor average flow and operator licensing needs.

System Growth Can Change Required Operator Level

For example, if a Category I system grows beyond 100,000 gpd average flow, it can move into Category II.

This raises the minimum supervisory license requirement from:

• Collection I or Wastewater D

to:

• Collection II or Wastewater C.

Collection System Components

Collection-system operators may be responsible for equipment such as:

• gravity sewer mains;
• manholes;
• service connections;
• lift stations;
• force mains;
• pumps;
• valves;
• alarms;
• backup power.

Gravity Sewer Systems

Gravity sewers use slope to convey wastewater.

Operators should recognize conditions that can reduce capacity, including:

• grease;
• roots;
• debris;
• sediment;
• pipe collapse;
• infiltration and inflow.

Lift Stations

Lift stations pump wastewater when gravity flow alone cannot move sewage to the next location.

Operators should monitor:

• wet-well levels;
• pump operation;
• pump alternation;
• alarms;
• power supply;
• odor;
• backup systems.

Lift-Station Failure

Failure of a lift station can quickly cause:

• sewer backup;
• sanitary sewer overflow;
• environmental release;
• public-health risk.

Standby Pumps

Operators should know whether a lift station includes:

• duty pumps;
• standby pumps;
• automatic alternation;
• emergency bypass pumping capability.

High-Level Alarms

A high wet-well level alarm warns that the lift station may be approaching an overflow condition.

The alarm should trigger investigation and response, not merely acknowledgment.

Power Failure

Collection-system reliability depends heavily on electrical power at lift stations.

Emergency provisions can include:

• permanent generators;
• portable generators;
• quick-connect equipment;
• backup pumping;
• emergency response procedures.

Force Mains

A force main carries wastewater under pressure from a pump station.

Operators should watch for:

• pressure changes;
• leaks;
• air accumulation;
• valve problems;
• pipe failure.

Sanitary Sewer Overflows

A sanitary sewer overflow, or SSO, occurs when wastewater escapes from the collection system before reaching the treatment facility.

Possible causes include:

• blockages;
• grease;
• roots;
• pump failure;
• power failure;
• excessive infiltration and inflow;
• structural failure.

Overflow Prevention Is a Major Collection Responsibility

Preventive maintenance reduces the risk of SSOs.

Programs can include:

• cleaning;
• inspection;
• root control;
• grease control;
• lift-station maintenance;
• alarm testing;
• pipe rehabilitation.

Infiltration

Infiltration is groundwater entering the collection system through defects such as:

• cracked pipes;
• bad joints;
• manhole defects;
• service-line defects.

Inflow

Inflow is stormwater entering through direct connections or openings such as:

• roof drains;
• storm-drain connections;
• open manholes;
• sump pumps;
• other improper connections.

Why I&I Matters

Excessive infiltration and inflow can:

• increase lift-station run time;
• cause collection-system surcharging;
• cause SSOs;
• hydraulically overload the treatment plant;
• increase treatment costs.

Collection System Inspection

Operators can inspect collection systems using methods such as:

• visual manhole inspection;
• CCTV inspection;
• smoke testing;
• dye testing;
• flow monitoring.

Preventive Cleaning

High-risk sewer segments can require routine cleaning to prevent:

• grease accumulation;
• solids deposition;
• blockages.

Collection System Safety

Wastewater collection work can expose operators to significant hazards.

Examples include:

• confined spaces;
• hydrogen sulfide;
• oxygen deficiency;
• traffic;
• electrical hazards;
• biological hazards;
• moving equipment.

Hydrogen Sulfide

Hydrogen sulfide can accumulate in sewers, wet wells, and manholes.

It can cause:

• odor;
• corrosion;
• serious health effects;
• death at high concentrations.

Confined-Space Entry

Operators should follow applicable confined-space procedures before entering manholes, wet wells, and other confined spaces.

Atmospheric testing and ventilation can be critical safety requirements.

Collection Operator Class I

Collection Class I is the entry-level Texas wastewater collection license.

TCEQ currently requires the approved Wastewater Collection training course for this license.

Collection Operator Class II

Collection Class II requires additional wastewater training and qualifying experience beyond Class I.

Training includes Basic Wastewater Operation and Wastewater Collection, plus applicable additional coursework.

Collection Operator Class III

Collection Class III is the highest Texas wastewater collection operator license.

It requires more extensive education, experience, and training than Classes I and II.

Collection License Exam

Texas currently administers collection-system operator exams through approved computer-based testing centers.

The available exams include:

• Class I Wastewater Collection System Operator;
• Class II Wastewater Collection System Operator;
• Class III Wastewater Collection System Operator.

Passing Score

The current minimum passing score for TCEQ occupational licensing exams is:

70 percent

Collection Class III Is Not Equivalent to Wastewater Class A

Collection licensing and treatment licensing use separate class structures.

The highest collection license is:

Collection Class III

The highest wastewater treatment license is:

Wastewater Class A

Why Category III Requires Only Wastewater Class B

The TCEQ equivalency table for collection-system supervision allows a Wastewater Class B operator to satisfy the minimum operator requirement for a Category III collection system.

A Wastewater Class A operator would also exceed the minimum.

Operator in Direct Supervision

The key licensing requirement applies particularly to personnel directly supervising operation and maintenance crews.

A system should therefore clearly identify qualified supervisors for collection activities.

Contract Operations

A utility may use contracted personnel for collection-system operation or maintenance.

Contracting does not eliminate the requirement for properly licensed supervision.

Operations Companies

A nongovernmental organization contracting to operate wastewater collection systems can be subject to TCEQ wastewater operations company registration requirements.

Records

Collection-system operational records can include:

• lift-station inspections;
• pump maintenance;
• alarm tests;
• sewer cleaning;
• blockage response;
• SSO response;
• CCTV inspections;
• repairs;
• generator tests.

Example: Category I System Supervised by Wastewater Class D

This meets the minimum operator-level requirement because Category I accepts either Collection Class I or Wastewater Class D.

Example: Category II System Supervised by Collection Class I

This does not meet the minimum requirement.

Category II requires at least:

• Collection Class II; or
• Wastewater Class C.

Example: Category II System Supervised by Wastewater Class B

This meets the requirement because Wastewater Class B is higher than the minimum Wastewater Class C level.

Example: Category III System Supervised by Wastewater Class C

This does not meet the minimum requirement.

Category III requires at least:

• Collection Class III; or
• Wastewater Class B.

Example: Category III System Supervised by Wastewater Class A

This meets the requirement because Class A exceeds the minimum Class B treatment license requirement.

Example: System Grows from 90,000 to 150,000 gpd

The system crosses the 100,000 gpd threshold and moves from Category I to Category II.

The minimum operator requirement therefore increases.

Example: Flow Reaches Exactly 1.0 MGD

The system remains Category II because Category III applies to flow greater than 1.0 MGD.

Example: Flow Reaches 1.01 MGD

The system falls into Category III.

Common Collection-System Classification Mistakes

• Confusing Categories I, II, and III with treatment facility Categories D, C, B, and A.
• Using instantaneous flow instead of daily average flow.
• Classifying exactly 100,000 gpd as Category I.
• Classifying exactly 1.0 MGD as Category III.
• Assuming a Collection Class I operator can supervise any collection system.
• Assuming wastewater treatment licenses cannot qualify for collection-system supervision.
• Assuming a collection license automatically authorizes wastewater treatment plant operation.
• Failing to increase supervisory licensing when system flow grows into a higher category.
• Ignoring collection-system maintenance because treatment occurs elsewhere.
• Failing to provide licensed supervision for collection operation and maintenance crews.

A Practical Classification Review

1. Determine the collection system daily average flow.
2. Compare flow with 100,000 gpd.
3. Compare flow with 1.0 MGD.
4. Determine Category I, II, or III.
5. Determine the minimum Collection license.
6. Determine the equivalent minimum Wastewater Treatment license.
7. Verify supervisory personnel meet or exceed the requirement.

A Practical Collection Operations Review

1. Review lift-station status.
2. Review alarms.
3. Review standby pumps and backup power.
4. Review recent blockages.
5. Review sewer cleaning.
6. Review I&I indicators.
7. Review overflow history.
8. Review maintenance records.
9. Verify licensed supervisory coverage.

What to Remember for the Exam

• Texas wastewater collection systems use Categories I, II, and III.
• Category I is less than 100,000 gpd.
• Category I requires at least Collection Class I or Wastewater Class D.
• Category II is 100,000 gpd through 1.0 MGD.
• Category II requires at least Collection Class II or Wastewater Class C.
• Category III is greater than 1.0 MGD.
• Category III requires at least Collection Class III or Wastewater Class B.
• Exactly 100,000 gpd is Category II.
• Exactly 1.0 MGD remains Category II.
• A flow greater than 1.0 MGD is Category III.
• At least one collection supervisor must hold a license equal to or higher than the minimum required for the system category.
• Direct supervisors of collection operation and maintenance crews must hold an appropriate collection or wastewater treatment license.
• A wastewater treatment license can qualify an operator for collection-system supervision when its class meets the required level.
• A collection license does not automatically authorize wastewater treatment plant operation.
• Collection Categories I through III are different from treatment facility Categories D through A.
• Collection systems include sewers, manholes, lift stations, force mains, pumps, alarms, and related equipment.
• Infiltration is groundwater entering through defects; inflow is stormwater entering through direct connections or openings.
• Excessive I&I can cause SSOs and hydraulic overload at the treatment plant.
• Collection Class III is the highest Texas collection-system operator license.
• The current minimum passing score for applicable TCEQ operator licensing exams is 70 percent.