Recycling Treated Domestic Wastewater and Mobile Drinking Water Treatment System Wastewater

Operators of oil and gas wells may obtain a permit from the Railroad Commission (“RRC”) to recycle domestic wastewater (“DWW”) or wastewater produced by mobile drinking water treatment systems (“MDWTS”). These treated wastewater streams may be recycled for the following purposes:

• Down-hole applications:
  • Drilling fluid make-up water to be used after the surface casing has been set through the base of usable quality
  • Make-up water for cement.
  • Make-up water for hydraulic fracturing fluid.
• Surface applications:
  • Dust suppression for the drill pad or roads.
  • Controlled (non-atomized) irrigation.

Since April 2016 these permits have been issued under the minor permit provision of 16 Texas Administration Code §3.8(d)(6)(G). Minor permits are limited in duration for 60 days. Operators may still apply for a location-specific minor permit. For more information please see the page for Minor Permits, Hydrostatic Test Discharges, Domestic Wastewater, & Other Permits.

Beginning on July 18, 2022, the RRC will also issue District-Wide Permits under the authority of 16 Texas Administration Code §3.8(d)(C)(G)(i), which states, “Treated fluid may be reused in any manner… pursuant to a permit issued by the director on a case-by-case basis, taking into account the source of the fluids, the anticipated constituents of concern, the volume of fluids, the location, and the proposed reuse of the treated fluids.”

Domestic Wastewater

“Domestic wastewater” (DWW) means wastewater that originates primarily from kitchen, bathroom, and laundry sources, including waste from food preparation, dishwashing, garbage grinding, toilets, baths, showers, and sinks of a residential dwelling.

The RRC has jurisdiction over the on-site treatment and management of domestic wastewater generated at oil and gas drill sites pursuant to 16 Texas Administrative Code §3.30(d)(1). The RRC’s jurisdiction is limited to DWW facilities with a daily capacity of 5,000 gallons per day or less, consistent with TCEQ rules; facilities with capacities greater than 5,000 gallons per day are under the jurisdiction of TCEQ (see 30 Texas Administrative Code §285.3(g)(1)).

Solids accumulated during the treatment of domestic sewage must be transported by a TCEQ registered sludge transporter that is authorized to transport domestic sewage to a TCEQ-permitted disposal facility authorized to receive and manage domestic sewage.

A RRC permit is required to recycle treated DWW for downhole and surface application (dust suppression and controlled irrigation). Treated DWW is not authorized for re-use as rig wash, and direct human exposure must be avoided.

Figure 1 describes the regulatory jurisdiction for DWW at oil and gas well sites.

Wastewater from Mobile Drinking Water Treatment Facilities

“Mobile drinking water treatment system wastewater” (MDWTS) means wastewater generated from the treatment of ground of surface water for drinking water purposes.

TCEQ has jurisdiction over the treatment of water treated for drinking water, other potable uses, and potable water delivery.

Wastewater generated by MDWTS associated with oil or gas production is regulated by the RRC in accordance with 16 Texas Administrative Code §3.30(b)(2)(A)(i).

A RRC permit is required to recycle treated MDWTS for surface application (dust suppression and controlled irrigation). If mobile drinking water treatment system wastewater is exclusively reincorporated into the non-potable water from the supply well from which it came, no permit is required for use as rig wash or for down-hole purposes.

Figure 2 describes the regulatory jurisdiction for MDWTS at oil and gas well sites.

District-Wide Permit

This permitting program is designed to enable the P-5 operator of record to apply to obtain one permit that may be used at one or multiple well sites in one RRC District that is being served by the same wastewater treatment service provider.

• The permit application will be by letter.
• The permit will be issued to the P-5 operator of record (the “applicant”). An applicant must have an active Organization Report (Form P-5) with the RRC. Contact the P-5 Department at 512-463-6772 or p5@rrc.texas.gov for any questions regarding the Form P-5.
• A separate permit will be required for recycling activities in another RRC District or with another service provider.
• A change in service providers will require a new permit.
• The operator may request that the service provider is included on all communications from the RRC, and the RRC will honor such a request.
• The service provider will also be required to sign the application.
• The operator will file monthly reports documenting the treatment and recycling activities at all locations on a spreadsheet, available on our Monitoring and Reporting page. The monthly reports will include treatment locations, sampling, and analysis results.
• Treated wastewater may only be recycled for use for the purposes authorized in the permit.
• The permit term will be one year and may be renewed.

The RRC reserves the right to modify a permit as determined by site specific conditions or to cancel a permit should investigation determine that such authorization is being abused.

Waste Testing and Treatment Standards

The following waste testing and treatment standards will be used for all permits issued in this program.  If treated DWW and MDWTS wastewater are commingled, the more stringent requirements will apply unless otherwise indicated. 

Mobile Drinking Water Treatment System Wastewater

• For MDWTS that will be recycled for use down-hole, a permit is not required
• For MDWTS that will be recycled for use by surface application as dust suppression or controlled irrigation, the required analysis is as follows:
  • One (1) sample collected and analyzed every 30 days.
  • If the Treatment System is on location less than 30 days, at least one (1) sample must be collected and analyzed.
  • Dust suppression and controlled irrigation must cease if vegetation shows signs of stress or damage.
  • The samples will be analyzed as follows with the limitations not to be exceeded:

    MDWTS Recycled for Dust Suppression or Controlled Irrigation
    Parameter	Limitation
    Total Dissolved Solids (TDS) Standard Method 2540 or equivalent	Report
    pH EPA Method 9045C or equivalent	6.0 to 9.0 standard units
    Electrical Conductivity (EC) Louisiana Dept. of Natural Resources Lab Procedures for Analysis of Exploration & Production Waste or equivalent	≤ 4.0 mmhos/cm

Domestic Wastewater

• For DWW that is recycled for use down-hole the required analysis is as follows:
  • One (1) sample must be collected and analyzed every 14 days.
  • If the Treatment System is on location less than 14 days, at least one (1) sample must be collected and analyzed.
  • The permittee must specify whether the treated fluids have been stored more than 7 days.
  • The samples will be analyzed as follows with the limitations not to be exceeded:

    DWW Recycled for Down-hole Use
    Parameter	Limitation
    Escherichia coli (E. coli) EPA Method 9223 enzyme substrate coliform test or equivalent	≤ 800 CFU/100 milliliters (ml)
    Chlorine Residual (> 7-day storage) EPA Method 334.0 or equivalent	2 - 3 mg/l
    pH EPA Method 9045C or equivalent	6.0 - 9.0 Standard Units (SU)

• For DWW re-used for surface application as dust suppression and/or controlled irrigation the required analysis is as follows:
  • One (1) sample must be collected and analyzed every 7 days.
  • If the Treatment System is on location less than 7 days, at least one (1) sample must be collected and analyzed.
  • Dust suppression and controlled irrigation must cease if vegetation shows signs of stress or damage.
  • The samples will be analyzed as follows with the limitations not to be exceeded:

    DWW Recycled for Dust Suppression or Controlled Irrigation
    Parameter	Limitation
    E. coli for “Dust Suppression” EPA Method 9223 enzyme substrate coliform test or equivalent	≤ 200 CFU/100 ml
    E. coli for “Controlled Irrigation” EPA Method 9223 enzyme substrate coliform test or equivalent	≤ 75 CFU/100 ml
    Electrical Conductivity (EC) Louisiana Dept. of Natural Resources Lab Procedures for Analysis of Exploration & Production Waste or equivalent	≤ 4.0 mmhos/cm
    Total Dissolved Solids (TDS) Standard Method 2540 or equivalent	Report
    Chlorine Residual (> 7-day storage) EPA Method 334.0 or equivalent	2 - 3 mg/l
    pH EPA Method 9045C or equivalent field method	6.0 – 9.0 SU

Treatment Unit and Recycling Location Restrictions

The DWW and MDWTS treatment units must be located on a well pad.

The irrigation areas and dust suppression locations must not be located:

• Within a 100-year floodplain;
• In a watercourse; or
• In a sensitive area as defined by 16 TAC §3.91.

The irrigation areas and dust suppression locations must be located:

• Above the top of the seasonal high-water table;
• At least 150 feet from surface water, domestic wells, or irrigation wells; and
• At least 500 feet from a public water supply well.