No. 30383 (Amendment): R317-4-9. Absorption Systems

DAR File No.: 30383
Filed: 08/30/2007, 04:30
Received by: NL

RULE ANALYSIS

Purpose of the rule or reason for the change:

The purpose of this amendment is to update this section to make it more generic to apply to a broader range of wastewater absorption systems and replace an outdated reference with a more descriptive one.

Summary of the rule or change:

The changes are: 1) at the option of the local health department or district, a gravelless chamber trench wastewater absorption system can be used in lieu of standard gravel and effluent pipe; 2) grant a 30% reduction of drainfield size when this type of system is used; and 3) use International Association of Plumbing and Mechanical Officials (IAPMO) Standard PS 63-2005 as the new referenced standard.

State statutory or constitutional authorization for this rule:

Section 19-5-105

This rule or change incorporates by reference the following material:

International Association of Plumbing and Mechanical Officials (IAPMO) Standard 63-2005

Anticipated cost or savings to:

the state budget:

None--The proposed changes modify a technical specification and will not result in any costs or savings to the state budget.

local governments:

None--The proposed changes modify a technical specification and will not result in any costs or savings to local government.

small businesses and persons other than businesses:

If a gravelless chamber trench system is allowed by the local health department or district, a 30% reduction in drainfield size can be granted for a Type "A" Chamber. For a Type "B" Chamber, approximately 5% more drainfield product will need to be purchased and installed by the consumer. Actual costs or savings cannot be estimated, as it depends on the amount that is required for their particular project. For example a four-bedroom home will require less drainfield (gravelless chambers) than a five-bedroom home.

Compliance costs for affected persons:

If a gravelless chamber trench system is allowed by the local health department or district, a 30% reduction in drainfield size can be granted for a Type "A" Chamber. For a Type "B" Chamber, approximately 5% more drainfield product will need to be purchased and installed by consumer. Actual costs or savings cannot be estimated, as it depends on the amount that is required for their particular project. For example a four-bedroom home will require less drainfield (gravelless chambers) than a five-bedroom home.

Comments by the department head on the fiscal impact the rule may have on businesses:

The proposed amendments are not anticipated to have any impact on business costs, as the consumer will be most affected either in cost or savings. Rick Sprott, Executive Secretary

The full text of this rule may be inspected, during regular business hours, at the Division of Administrative Rules, or at:

Environmental Quality
Water Quality
CANNON HEALTH BLDG
288 N 1460 W
SALT LAKE CITY UT 84116-3231

Direct questions regarding this rule to:

Dave Wham at the above address, by phone at 801-538-6052, by FAX at 801-538-6016, or by Internet E-mail at [e-mail]

Interested persons may present their views on this rule by submitting written comments to the address above no later than 5:00 p.m. on:

10/15/2007

This rule may become effective on:

10/22/2007

Authorized by:

Walter Baker, Director

RULE TEXT

R317. Environmental Quality, Water Quality.

R317-4. Onsite Wastewater Systems.

R317-4-9. Absorption Systems.

 

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9.3. Shallow Trenches with Capping Fill. Shallow trenches with capping fill are trenches which meet the requirements of standard trenches except for depth of installation. Shallow trenches with capping fill may be installed to a minimum depth of 10 inches from the natural existing grade to the bottom of the trench. The top of the distribution pipe shall not be installed above the natural existing grade. The gravel fill above the pipe, the filter media barrier, and the soil fill are installed as a "cap" to the trench above grade. Fill shall be installed between trenches to prevent surface ponding and to provide a level finished grade.

[9.4. Chambered Trench Systems.

A. At the option of the local health department, chamber system media may be used in lieu of the gravel fill and perforated distribution pipe in absorption trenches if the installation is in conformance with manufacturer recommendations, as modified by these rules.

B. No cracked, weakened or otherwise damaged chamber units shall be used in any installation.

C. All chambers shall be manufactured of an approved material and shall be certified to withstand the AASHTO H-10-44 highway structural rating without damage or permanent deformation.

1. Type A Chamber Media:

a. Type A Chamber Media shall be of an approved design with a minimum width at the bottom of 30 inches (76 cm) and a minimum louvered sidewall opening height of six inches (15 cm).

b. Type A chamber media may be installed in standard trenches, shallow trenches with capping fill, at-grade trenches, and earth-fill trenches.

c. Type A chamber media shall be installed in trenches with a minimum excavation width of 36 inches (91 cm).

d. The minimum total length of Type A chamber media installed shall be equal or greater than the minimum length of a 36 inch wide gravel media trench as required by these rules.

2. Type B Chamber Media:

a. Type B Chamber Media shall be of an approved design with a minimum open bottom width of 18 inches (46 cm) and a minimum louvered sidewall opening height of 9-3/8 inches (24 cm).

b. The local health department shall provide written notification to the owner that they are using technology which has less experience than the conventional gravel filled trench. The potential liabilities of the system shall be clearly explained, including the responsibility a homeowner has to replace a failing wastewater system.

c. Type B chamber media may only be installed in standard trenches and shallow trenches with capping fill. Type B chambers may not be installed in conjunction with any other absorption system configuration, including alternative and experimental systems.

d. Type B chamber media shall be installed in trenches with a minimum excavation width of 24 inches (61 cm).

e. The bottom of the Type B chamber media and trench excavation shall be a minimum of 9-3/8 inches below the bottom invert of the effluent inlet pipe to the trench.

f. The minimum total length of Type B chamber media installed shall be equal or greater than the minimum length of a 36 inch (91 cm) wide gravel media trench as required by these rules.]9.4 Gravelless Chamber Trench

A. At the option of the local health department or district, gravelless chambers may be used in lieu of the gravel media and perforated effluent pipe in gravity absorption trenches or gravel media when a pressurized distribution pipe system is used, the installation is in conformance with manufacturer recommendations, as modified by these rules.

B. No cracked, weakened, modified or otherwise damaged chamber units shall be used in any installation.

C. All Chamber endplates shall be designed so that the bottom elevation of the effluent inlet pipe is at an equal or higher elevation than the highest elevation of the chamber sidewall louvers.

D. All chambers shall have a splash plate under the inlet pipe or other design feature to avoid unnecessary channeling into trench bottom.

E. An observation port may be placed in each drainfield line to observe the infiltrative surface conditions and ponding levels within the drainfield.

F. All chambers shall meet international Association of Plumbing and Mechanical Officials (IAPMO) standard PS 63-2005, which is hereby incorporated into this rule by reference.

1. Type A Chamber:

a. Shall have a minimum chamber width of 30-inches.

b. Shall be installed in trenches with a maximum excavation width of 36 inches.

2. Type B Chamber:

a. Shall have a minimum chamber width of 22-inches.

b. Shall be installed in trenches with a maximum excavation width of 24 inches.

G. Absorption area shall be calculated using a trench width of 36 inches for Type A Chambers and 24 inches for Type B Chambers. In each case an additional reduction factor may be applied to the calculated absorption area by using a 0.7 multiplier.

9.5. Deep Wall Trenches.

A. Deep wall trenches may be constructed in lieu of other approved absorption systems or as a supplement to an absorption trench where soil conditions and the required separation from the maximum ground water table comply with Table 11 of this section. This absorption system consists of deep trenches filled with clean, coarse filter material which receive septic tank effluent and allow it to seep through sidewalls into the adjacent porous subsurface soil. They shall conform to the following requirements:

1. The effective absorption areas shall be considered as the outside surface of the deep wall trench (vertical sidewall area) calculated below the inlet or distributing pipe, exclusive of any unsuitable soil or bedrock formations. The bottom area and any highly restrictive or impervious strata or bedrock formations shall not be considered in determining the effective sidewall absorption area. Each deep wall trench shall have a minimum sidewall absorption depth of 2 feet of suitable soil formation.

 

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KEY: waste water, onsite wastewater systems, alternative onsite wastewater systems, septic tanks

Date of Enactment or Last Substantive Amendment: [May 19, 2006]2007

Notice of Continuation: February 10, 2005

Authorizing, and Implemented or Interpreted Law: 19-5-104