Water system assessments and gap analysis in Texas

What it covers

This page is for an existing water system: a city or town, a district, a water supply corporation or another small public water system. We review the records and meters, rate the condition of each facility, build a hydraulic model and study water loss. The gap analysis is the difference between what the system has and what it needs: the TCEQ minimums under 30 TAC Chapter 290, the demand it serves now and the demand coming.

The answer is a ranked list of repairs with cost estimates the owner can budget and take to a funder. For a new system or a new well, see public water system design. For new mains, loops and fire flow fixes, see water distribution.

When you need one

• The system loses more water than it bills.
• Pressure drops at the far end of the system or on high ground as it grows.
• A developer asks for service, and you need to know whether the wells, storage and pumps can carry the new connections.
• A tank's coating has failed or its structure shows wear.
• TCEQ has issued a notice of violation, which sets a time frame to respond.
• A funding deadline is coming and you do not yet have a project defined.

What we check

• Capacity. 30 TAC §290.45 sets minimum well capacity, storage and service pump capacity per connection, in tiers by connection count. We check the current count and the buildout count against them. They are minimums, not a design.
• Pressure and fire flow. The system must be designed for at least 35 psi at 1.5 gallons per minute per connection, and 20 psi under combined fire and drinking water flow where it provides fire protection (§290.44(d)). We check both in a hydraulic model, usually EPANET, and compare it with a hydrant flow test where one exists. A model with no field data is reported as unvalidated.
• Wells. Separation distances from sewers, septic systems and treatment plants, and the sanitary control easement within 150 feet of the well (§290.41(c)).
• Tanks. TCEQ requires each ground, elevated and pressure tank to be inspected every year by system staff or a contracted inspection service (§290.46(m)(1)). We read those reports and check coating and structural condition.
• Water loss. We separate real losses, such as leaking mains and service lines, from apparent losses, such as meter error and billing mistakes. Texas sets water loss thresholds per connection under TWDB's rules (31 TAC §358.13), and an audit must be on file with TWDB on its schedule (§358.11).
• Age and condition. When each main, well, tank and pump went in, what shape it is in and when it needs replacing.

What we do

1. Gather the records. Meter and billing data, system maps, past audits, tank inspection reports and maintenance logs. Where records are thin, we use operator knowledge, old drawings and a site walk.
2. Walk the facilities. We rate the condition of each well, tank, pump station and treatment unit with your staff.
3. Model the system. We build or update a hydraulic model and check pressure and fire flow at today's demand and with planned growth added.
4. Study water loss. A desk audit first, then field checks where the numbers are rough, so field time goes where the losses are.
5. List the gaps. Each gap gets its driver: compliance, capacity, condition or efficiency. Compliance items go first because a regulator sets the date.
6. Rank and price the fixes. We phase the list by when each project has to happen and attach an engineer's opinion of probable cost to the top projects. Those estimates can grow into the preliminary engineering report a funder asks for.

What you get

• An assessment report covering condition, capacity, pressure, fire flow and water loss, with each finding tied to the rule or criterion it was checked against.
• A ranked, phased list of repairs with cost estimates the owner can budget and fund.
• The hydraulic model, and the water loss analysis behind the report.
• A report checked by an engineer who did not write it, and sealed by a Texas licensed professional engineer when it is submitted to a regulator or relied on for design.

Paying for the fixes

• TWDB's Drinking Water State Revolving Fund finances projects that correct deficiencies in water quality, capacity, pressure and water loss. Solicitation opens in December and closes in March. A project without a Project Information Form in by the deadline is left off the initial project priority list. Principal forgiveness is available to disadvantaged communities and very small systems.
• USDA Rural Development makes water and waste loans and grants to public bodies in rural areas and towns of 10,000 people or fewer, and requires a preliminary engineering report with the application.
• The engineering comes first. Funders want an engineering report, a cost estimate and a project that fits their rules. The ranked list and its cost estimates are where that report starts.
• Water loss can decide funding. A Texas utility that has not filed a complete water loss audit cannot get TWDB help for a water supply project until one is accepted. If its losses meet or exceed its threshold, part of the money must go to reducing them unless TWDB grants a waiver.

What affects time and cost

• Records. Good meter, billing and maintenance records shorten the desk work. Thin records mean more time in the field.
• Metering. An unmetered system needs some metering before it can track losses at all.
• The number of facilities. Each well, tank and pump station is another site to walk and rate.
• Field data. A hydrant flow test lets us validate the model. Without one, the model is reported as unvalidated.
• The funding calendar. A project has to be defined before the program window closes, so the deadline you aim for sets the order of the work.