Plumber Flower Mound: The Three Months That Price Your Whole Year
Almost everywhere else, a plumbing leak is a bad month. In Flower Mound it can be a bad year, and whether it is depends on a date that nobody chose for you. The town sets your residential sewer rate once annually from your winter water use, and the exact three month window it measures is decided by the first digit of your utility account number.
That single mechanism changes the priority order of every small plumbing fault in this town between the middle of November and the middle of March. This page sets out how it works, what the town publishes about it, and the rest of what Flower Mound puts on the record about its water and sewer system. Everything here comes from town pages, and where we have done the arithmetic ourselves we say so.
Why a plumber Flower Mound residents call in January is worth more than one in July
The town explains it plainly. Once a year it calculates residential water usage to determine sewer rates for the following year, and the rate is based on average water usage across a window running somewhere between mid November and mid March, chosen because that is when consumption is generally lowest. Sewer volume is not metered. Winter water use is the proxy for it.
Six windows exist and the town publishes which one applies to you by the first digit of your account number. Accounts starting with a three are measured from 1 December to 1 March. Four runs 5 December to 5 March, five runs 10 December to 10 March, six runs 15 November to 15 February, seven runs 20 November to 20 February and eight runs 25 November to 25 February. The town adds that the actual meter read may fall two to four days before the billing date.
Now put a fault into that. A toilet flapper that runs intermittently, a slab leak that has not yet surfaced, a dripping outside bib nobody checks in winter, a water softener stuck in regeneration. In July that inflates one bill. Inside your averaging window it inflates the number the town then divides by for the next twelve sewer bills.
The town names the biggest single cause itself, and it is not a fault at all. It says using a sprinkler system during the window is one of the major factors that will cause your sewer rate to increase, and asks residents to refrain from irrigating then because most plants and grasses are dormant. If you must water, it says, expect your averaging to come out high.
What this actually changes about how you handle a small leak here
Two houses on the same street can sit in different windows, because the windows key on the account number rather than on the address or the meter reading route. So neighbourly advice about timing is unreliable in Flower Mound in a way it is not elsewhere. Check your own bill for your own account number before you assume your dates.
The practical order of work changes too. Outside the window, a slow leak is a repair you can schedule around your diary. Inside it, the same leak has a compounding cost, and finding it quickly is worth more than finding it conveniently. That is a straightforward argument for locating the leak properly rather than waiting to see whether the next bill looks odd, because by the time the bill looks odd the averaging period may already have absorbed it.
It also means the annual pre-winter check is a real thing in this town and not a marketing habit. Toilets, outside bibs, irrigation zone valves, pressure regulators, water softener cycles and any known slow drip are all worth clearing before your window opens, because a fault fixed on 10 November and a fault fixed on 10 January have very different price tags.
How the averaging and the rate fit together
The minimum covers you to 2,000 gallons. Above that you are billed per thousand gallon unit, and the volume it is billed against is your winter average rather than your current month. That is the piece most people miss when they compare a summer water bill to a summer sewer bill and find the two moving differently.
It also explains a common complaint that is not a billing error. If your sewer charge stays high through a summer in which you used very little water indoors, the likely cause is not the meter. It is that something inflated the average during the previous winter window, and the town is still dividing by that number.
The reverse is worth knowing too. Fixing a genuine leak in February does not reduce this year sewer bill much, because the average is already largely fixed. It reduces next year. Neither of those is a reason to delay a repair, but both are reasons to understand what you are looking at before you spend an afternoon arguing with a statement.
None of this touches the water side of the bill, which is metered normally. It is specifically the sewer component that runs on the average, because there is no meter on what leaves the house.
The service line inventory, which Flower Mound actually finished
Most cities this site has written up cannot tell you how many lead service lines they have. Flower Mound can, and the answer is none. The town states it has completed inspecting all 23,904 of its water service lines to comply with the federal rules aimed at reducing lead exposure, and that none of the service lines in the town are classified as lead or unknown.
The work sits under the Lead and Copper Rule Revision, which required providers to verify whether town owned service lines connecting the water main to the meter contain lead, and to produce an inventory by October 2024 that also covers privately owned lines running from the meter to the building. The inventory has been submitted to the Texas Commission on Environmental Quality. The four designations the EPA uses are lead, galvanized requiring replacement, unknown, and non-lead.
The town is careful about the caveat and so are we. It says the information in the inventory is subject to change, and that if it later determines a line contains lead, is of unknown material, or includes galvanized piping that was or could have been downstream from a lead source, it will contact the customer directly.
For scale, Buffalo in New York, which this site wrote up in the same batch, publishes no service line count at all and we had to refuse the figure entirely there. A finished inventory with a zero in it is a genuinely useful thing for a homeowner deciding whether an old house needs supply pipework replaced for lead reasons rather than for pressure or corrosion reasons.
Where the water comes from, and why two houses can get different water
Flower Mound does not treat its own drinking water. It receives treated water from the Upper Trinity Regional Water District and from Dallas Water Utilities and then delivers it, testing it regularly and reporting the results to the EPA and to the public through an annual water quality report.
The two suppliers do not do the same thing. The town states that Upper Trinity, which provides most of its drinking water, does not add fluoride, while Dallas Water Utilities does. It quotes Dallas Water Utilities describing water that naturally contains fluoride between 0.3 and 0.5 milligrams per litre, monitored and adjusted at its treatment plants to reach the recommended level. The town adds that its own water quality reports show fluoride levels in town water have been below 0.7 milligrams per litre.
We report that as a supply fact and make no health claim in either direction. It is on the page because a two supplier system is a real thing for a plumber to know about. Blended and switching supplies are one of the ordinary reasons that taste, smell and mineral behaviour can vary across a town and across a year without anything being wrong with the house.
We do not state a hardness figure for Flower Mound. The town publishes annual water quality reports going back several years and we did not open them, so there is no number here to quote and we will not estimate one from a supplier average.
What the town crews do, and where the page stops short
The Utility Line Maintenance team publishes its own remit and it is broader on the wastewater side than several cities on this site. On water distribution it lists inspection and replacement of meters, maintenance of water mains and service lines, maintenance of valves and fire hydrants, and responding to pressure complaints.
On wastewater collection it lists repairs to sewer mains and service lines, pressure cleaning and flushing of main lines and services, investigating causes of service line blockages, rehabilitation of sanitary sewer manholes, video inspection and smoke testing of mains and services to locate failures, and investigation of sewer odour complaints.
Two of those are worth flagging for anyone with a recurring problem. Smoke testing is how a collection system finds illicit connections and broken pipe from the surface, and if a crew smoke tests your street you may see vapour from vents or from a dry trap indoors, which is a diagnostic and not a fault. Investigation of odour complaints is a real municipal service here, which means a persistent smell is worth reporting rather than chasing privately from the start.
Grease, and a rule that catches commercial fit outs early
Grease traps or interceptors are required by the town for all food establishments. The requirement that catches people out is not the trap itself but its position: both the interceptor and the trap location must be approved, and both must be located outside the building. A design has to be submitted at the time of the permit application, not later when the kitchen is being fitted.
If you are converting a unit to food use in Flower Mound, that pushes an external drainage decision to the very front of the project, and it is the sort of thing that turns into an expensive redesign if it surfaces after the slab is poured or the yard has been landscaped.
On the residential side the town explains why it cares. Fats, oils and grease poured down kitchen drains accumulate inside sewer pipes, restrict flow, and can cause untreated wastewater to back up into homes and businesses or overflow from manholes into parks, yards, streets and storm drains. Its own advice is to avoid the garbage disposal, scrape scraps into the bin, cool grease before skimming or wiping it out, prewash with cold rather than hot water, and screen the sink and floor drains.
Household cooking oil is not a bin question here either. The town collects it kerbside as household hazardous waste through its contracted provider, on a booked pickup rather than a fixed round, which is a more useful answer than most cities give and worth knowing before somebody decides the drain is easier.
What to fix before your averaging window opens
This checklist is keyed to a date rather than to a symptom, which is unusual, and the date is your own. Start by finding the first digit of your utility account number and reading your window off the town table. Then work through this before that window starts, not during it.
- Find your account number and write down your datesThree, four and five start in December. Six, seven and eight start in November. Your neighbour may not share your window.
- Test every toilet for a silent leakA flapper that seeps rather than runs is the single most common invisible consumer, and it will not announce itself in cold weather when nobody is listening.
- Shut down and check the irrigation systemThe town names sprinkler use during the window as a major cause of a high sewer average, and dormant lawns do not need it. A stuck zone valve does the same damage without you knowing.
- Walk the outside bibs and the hose connectionsA slow winter drip outdoors goes unnoticed for months and still passes through the meter.
- Check the water softener cycle if you have oneA unit stuck regenerating can move a startling volume of water and it will sit inside the average unchallenged.
- Read the meter last thing at night and first thing in the morningWith nothing running, movement across those hours is the plainest evidence of a leak you can gather without tools.
- Deal with any known slow leak now rather than in FebruaryA repair before the window protects twelve bills. The same repair in February mostly protects next year.
- If a smell or a recurring blockage has been building, report itThe town investigates sewer odour complaints and service line blockage causes, and smoke testing and video inspection are services it already runs.
- Pull the water quality report if mineral behaviour matters to youSupply is blended between two wholesalers with different fluoride practice, so check the report rather than assuming a constant.
- Do not assume the boundary of town responsibilityThe published responsibility diagram is a graphic and the page text does not state the split. Ask Public Works about your address before a dispute rather than during one.
None of this is exotic. It is the ordinary annual check, moved to a specific date because in Flower Mound the calendar has a price attached to it that it does not carry elsewhere.
Around the town
Flower Mound sits in Denton County on the north shore of Lewisville Lake, in the corridor between Dallas and Fort Worth. Its own published contact point is 2121 Cross Timbers Road. The neighbouring cities this site has already written up are The Colony, which sits on the far side of the same lake and runs its own wastewater plant, and Frisco and Carrollton to the east.
The comparison with The Colony is the useful one, because the two towns answer the same question differently. The Colony owns and operates its own treatment plant and registers contractors annually. Flower Mound buys treated drinking water from two wholesalers and prices its sewer service off a winter average. Same lake, two completely different sets of things to get wrong.
Winter leak hunting
Inside the averaging window a hidden leak compounds across twelve bills. Leak detection
Recurring blockages
The town investigates service line blockage causes and video inspects mains. Drain cleaning
Lateral failures
Smoke testing and CCTV find the main side. The private side is still yours to prove. Sewer line repair
Out of hours
North Texas freeze events and slab leaks do not wait for the billing cycle. Emergency plumbing
Flower Mound plumbing and utility questions
All of the below is drawn from Town of Flower Mound published pages. Rates and programmes change on the town calendar, so confirm anything load bearing with Utility Billing or Public Works.
Once a year the town averages your residential water usage across a three month winter window and uses that average to set your sewer rate for the following year. Sewer flow is not metered, so winter water use stands in for it, chosen because consumption is generally lowest then.
It depends on the first digit of your utility account number. Accounts beginning 3 are measured 1 December to 1 March, 4 runs 5 December to 5 March, 5 runs 10 December to 10 March, 6 runs 15 November to 15 February, 7 runs 20 November to 20 February and 8 runs 25 November to 25 February. The town notes the actual read may occur two to four days before the billing date.
Most likely because your sewer charge is being billed against last winter average rather than against this month usage. If something inflated consumption during your averaging window, whether a leak, a stuck irrigation valve or ordinary winter watering, that number carries forward for the year. Fixing it now improves next year rather than this one.
The town explicitly asks residents to refrain from it during the averaging window, because most plants and grasses are dormant and do not need watering, and because irrigation during that period is one of the major factors that raises the sewer rate. It says that if you feel watering is necessary, expect your averaging to come out on the high side.
Effective 1 October 2025 the minimum residential sewer rate is 26 dollars and 42 cents for usage from zero through 2,000 gallons, with an additional 5 dollars and 37 cents per thousand gallon unit above 2,000 gallons. Confirm current rates with Utility Billing, since these change on the town fiscal calendar.
According to the town, no. It states it has completed inspecting all 23,904 of its water service lines and that none is classified as lead or as unknown, under the Lead and Copper Rule Revision, with the inventory submitted to the Texas Commission on Environmental Quality. The town adds that the inventory is subject to change and it will contact customers directly if that changes for their line.
The town does not treat its own water. It receives treated drinking water from the Upper Trinity Regional Water District, which supplies most of it, and from Dallas Water Utilities, then distributes and tests it. Upper Trinity does not add fluoride and Dallas Water Utilities does, and the town reports its own fluoride levels have been below 0.7 milligrams per litre.
The town requires grease traps or interceptors for all food establishments. Both the interceptor and the trap must be located outside the building, the location must be approved, and the design has to be submitted at the time of permit application. Plan that before the fit out rather than during it.
Almost certainly not. Smoke testing of mains and services to locate failures is one of the published functions of the Utility Line Maintenance team, alongside video inspection. It is how a collection system finds cracks and improper connections from the surface. If smoke appears inside your home during a test it usually points to a dry trap or an unsealed connection worth checking.
This page does not state it, deliberately. The town links to a repair responsibility document that is a graphic rather than readable text, and the page text does not set the boundary out in words. Rather than guess from the maintenance remit, ask Public Works about your specific service before you need the answer.
Sources, arithmetic and what this page does not claim
Related work on this site: leak detection covers the winter leak case, drain cleaning covers blockages, sewer line repair covers the lateral, and emergency plumbing covers out of hours. The state picture is on our Texas plumbing page.
The residential sewer averaging mechanism, the statement that the town calculates residential water usage once a year to determine sewer rates for the following year, the explanation that the window is chosen because consumption is generally lowest, and the six account number windows and their dates come from the Town of Flower Mound Sewer Averaging page.
The same page is the source for the note that the actual read date may occur two to four days prior to the billing date, for the statement that sprinkler use during the window is a major factor raising the rate, the request to refrain from irrigating, and the minimum rate of 26 dollars 42 cents through 2,000 gallons with 5 dollars 37 cents per additional thousand gallons effective 1 October 2025.
The completion of inspection across all 23,904 water service lines, the statement that none is classified as lead or unknown, the four EPA designations, the Lead and Copper Rule Revision inventory deadline of October 2024, the submission to the Texas Commission on Environmental Quality, and the caveat that the inventory is subject to change alongside a commitment to contact customers directly, all come from the Town of Flower Mound Drinking Water Quality page.
That same page is the source for the Upper Trinity Regional Water District and Dallas Water Utilities supply arrangement, and for the fluoride statements including the 0.3 to 0.5 milligram per litre natural range quoted from Dallas Water Utilities and the town own figure of below 0.7 milligrams per litre.
The Utility Line Maintenance remit on both the water distribution and wastewater collection sides, including meter inspection and replacement, maintenance of mains and service lines, valves and hydrants, pressure complaints, repairs to sewer mains and service lines, pressure cleaning and flushing, investigation of service line blockage causes, manhole rehabilitation, video inspection and smoke testing, and investigation of sewer odour complaints, comes from the Town of Flower Mound Sewer FAQ page.
The grease trap and interceptor requirement for all food establishments, the requirement that both locations be approved and outside the building, the requirement that a design be submitted at time of permit application, the description of how fats oils and grease accumulate and cause backups and manhole overflows, the residential do and do not list, and the household hazardous waste collection route for cooking oil come from the Town of Flower Mound Fats, Oils and Grease Program page. The 2121 Cross Timbers Road address is the town published contact address.
No water hardness figure is stated on this page. The town publishes annual water quality reports and none was opened, so no hardness, mineral or contaminant value is quoted from them. No water rate is quoted, because the water rate schedule was not opened. No permit or inspection fee is quoted for the same reason.
No boundary between town and property owner repair responsibility is asserted anywhere above. The town links to a repair responsibility document for a typical water and sewer service and the content behind that link is a graphic with no readable text equivalent, so the split is left unstated rather than inferred. No split between Upper Trinity and Dallas Water Utilities volumes is stated, no count of grease traps, manholes or miles of sewer main is stated, and no Fats Oils and Grease code section number is cited, because none of those appears on the pages read.
No office, address, crew, response time, guarantee or coverage claim of ours is stated for Flower Mound, and no testimonial or performance statistic appears anywhere above. Where this page describes the effect of the averaging window across twelve subsequent bills, that is a description of the published mechanism rather than a quoted town figure. Rates, windows and programmes change, so confirm current requirements with Town of Flower Mound Utility Billing or Public Works before relying on anything on this page.