550 Reserve St., Southlake, TX · hello@sundayirrigators.com
Field Guide
Eight guides on what the ground under a North Texas property actually does, written the way we would explain it standing in your yard. No gated downloads, no summaries that stop right before the useful part. The full text is on this page.
Index
Jump to a category, or read straight through. The guides are ordered the way problems usually present themselves: first the symptom you noticed, then the system behind it.
Three failures that look identical from the driveway, and the simple checks that separate them before you spend money on the wrong one.
Read the guideDiagnostics · Guide 01
Almost every irrigation complaint arrives in the same shape: part of the lawn is browning and part of it is fine. From the driveway, a broken head, a failing valve and an undersized water supply all produce the same brown stripe. They cost wildly different amounts to fix, and replacing the wrong component is the most common way homeowners spend money twice.
You can narrow it down in about twenty minutes with no tools beyond your controller and a bucket. The whole method rests on one question: how large is the failure? A single head, a whole zone, or every zone. Scale points to cause.
Put the controller in manual mode and run one zone at a time. Do not water the whole schedule; stand in the zone while it runs. Look for four things: heads that never pop up, heads that pop up but barely turn, mist instead of droplets, and rotors that fling water twenty feet past where they should stop. Write down what each zone does. Half of all diagnostics is simply having watched.
If everything else in the zone throws a normal pattern and one head is dribbling, flooding or aiming at the fence, the fault is at that head. Common causes: a cracked riser from a mower or a truck tire, a nozzle packed with the fine grit that comes through North Texas municipal lines after main work, a stuck wiper seal, or a head that has settled below grade so the spray hits turf instead of clearing it. Heads and nozzles are the cheapest parts in the system. If someone quotes a valve replacement for a single misbehaving head, ask what they saw that pointed to the valve.
Zone valves fail in specific, recognizable ways. A zone that will not come on at all while the others do is usually a solenoid that has burned out or a wire connection that corroded in a valve box that keeps filling with water. A zone that comes on weakly across every head, evenly, points to a diaphragm that is no longer seating or debris holding the valve partially open. A zone that keeps seeping after the cycle ends — you will find a permanently soft patch around the lowest head — is a valve that is not closing fully, and it will show up on your water bill long before it shows up on your lawn. A zone that hammers, thumps or shudders when it opens is usually a pressure problem masquerading as a valve problem, which brings us to the third case.
If all zones underperform, stop looking at parts. Check three things in order. First, the isolation valve at the point of connection — it gets closed during plumbing work and left half open. Second, static pressure at an outside hose bib with everything else off. Third, whether anything else in the house is drawing at the same time. Spray heads are designed around roughly 30 psi at the nozzle and rotors around 45 psi; above that you get fog that drifts away, and below it you get short throw and doughnut patterns where nothing lands near the head. Pressure that is too high is the quieter problem: it shreds nozzles, mists water off the property and shortens the life of every seal in the system. A pressure-regulating device at the valve or pressure-regulated bodies at each head solve it permanently. Adding heads never does.
Put five straight-sided containers around a zone and run it for fifteen minutes. Measure the depth in each. If one holds twice what another does, the problem is coverage and spacing, not any single part. In practice heads need to throw water to the next head — a nozzle that reaches only halfway there will leave a dry ring that no run-time increase will fix. That is a design correction, not a repair, and it is worth knowing which one you are buying.
The size of the failure is the first clue. Working down this order keeps you from replacing parts that were never the problem.
Pressure is too high at the nozzle. Regulate it before you replace anything.
Nozzle is too small for the spacing, or the head is throwing short. Coverage issue.
The zone valve is weeping. Water is running while the system is off.
Look underground before you look at the schedule. Lateral leaks rarely surface.
Drainage · Guide 02
Water does not choose. It goes to the lowest reachable point and stays there until it can leave by gravity or evaporate. If the same three-foot circle floods in every storm, that circle is the lowest reachable point on that part of the property, and nothing about it will improve on its own. The question is never why here. It is why the water cannot get out of here.
There is no fall. Surface drainage needs slope. As a working target, lawn areas want roughly 1–2% fall away from structures — about an inch of drop for every four to eight feet. Builders establish that at final grade; a decade of settlement, added flower beds, new sod on top of old sod and a raised patio can flatten or reverse it without anyone noticing.
The soil will not take it. Most of this region sits on expansive clay. Dry clay opens surface cracks and drinks fast for a few minutes, then the surface particles swell shut and infiltration falls to a small fraction of an inch per hour. Loam might absorb a moderate rain; clay sheds most of it. That is why properties here flood in short, intense storms even when the ground looks parched.
Something is holding it in. A fence with a solid bottom rail, a landscape border, a retaining wall without weep holes, a compacted path from foot traffic, a driveway apron poured slightly proud of the lawn. Any of them will dam water as effectively as a curb.
Too much water arrives at once. A roof is a collection surface. Every downspout that discharges within a few feet of the foundation concentrates a large volume into a small area of already saturated clay. Two downspouts landing in the same side yard will overwhelm a grade that would otherwise be adequate.
The shape and behavior of standing water tells you which cause you have. Water that sits sheet-flat and wide across a lawn is a grade problem. Water that sits in a narrow band against a hard edge is an obstruction. Water that appears only under a downspout, in a defined fan shape, is a volume and discharge problem. Water that lingers for days after the surface elsewhere has dried is a soil and compaction problem — often the old construction staging area, still compacted a decade later.
Timing matters too. Note how long it takes to clear. Standing water that drains in an hour or two is unpleasant. Standing water that persists 24 to 48 hours is killing turf roots, breeding mosquitoes, and if it is within about ten feet of the house, it is feeding moisture into the soil that supports your slab.
In order of how often it is the right answer: extend and redirect the downspouts; correct the grade so there is continuous fall to a legal discharge point; install a collection system — catch basins and solid pipe, laid to a minimum fall of about 1% (an eighth of an inch per foot) — where there is no surface route; add a French drain only where the problem is subsurface water and saturated soil rather than surface runoff. A French drain installed to solve a surface grade problem will disappoint you within two seasons, because fines migrate into unwrapped gravel and it silts closed.
The part homeowners underestimate: the discharge point. A pipe has to end somewhere legal, lower than where it started, and not on a neighbor. Where a property drains toward the street, a curb core is often the answer. Where it does not, the design gets harder, and that is exactly where an elevation shot beats a guess.
Standing water is a symptom of lost fall or a missing exit. Both are fixable; only one of them needs pipe.
Figures above are typical design practice for this region, not guarantees. Every property gets measured.
Foundations · Guide 03
This is the guide we would hand to every homeowner in Southlake, Colleyville and Keller if we could only hand out one. The soil across much of North Texas is expansive clay. Expansive means the mineral structure takes on water and grows, and gives up water and shrinks. The movement is not subtle and it is not theoretical: it is the reason doors stick in one season and swing free in another.
Clay swells when wet and contracts when dry. A slab-on-grade foundation rests on that soil. When the moisture content under the perimeter of the slab differs from the moisture content under the center, the two areas sit at slightly different elevations, and the slab has to accommodate the difference. In a long, dry North Texas summer the perimeter dries and shrinks faster than the protected interior, and the edges settle. After a wet stretch the perimeter swells and lifts. Repeat that cycle for years and you get cracked brick joints, separated crown molding, hairline diagonal cracks running from door corners, and windows that bind.
Nothing about that requires bad construction. It requires uneven moisture. Which is exactly what bad drainage produces.
A downspout dumping at the corner of the house keeps one small area of clay saturated through every wet month while the rest of the perimeter dries out. A rear yard that holds water for two days after each storm saturates one side of the slab while the street side sheds cleanly. A flower bed built up against the brick, watered daily on a drip line, holds a permanent wet band along one elevation. Each is a localized moisture anomaly, and localized moisture anomalies are the input that produces differential movement.
The mirror image is just as damaging. Large trees on one side of a house withdraw an enormous amount of water from clay during a hot, dry summer, shrinking soil on that elevation only. So do broken irrigation zones that have not run in months while the other side of the property has been watered all along. Consistency is the goal — not maximum dryness, and certainly not maximum wetness.
That last one surprises people. During an extended dry summer, running perimeter irrigation at low volume is protective, not wasteful. The failure mode homeowners rarely connect is turning off a system all summer to save money, then getting a foundation evaluation in the fall.
Drainage work is not a foundation repair, and no drainage contractor should tell you it is. If a slab has already moved, that is structural work and it belongs to a structural engineer. What drainage and grading do is remove the moisture variable — the thing that caused the movement and the thing that will cause it again after any repair. Any competent foundation contractor will ask about drainage first, and if yours did not, ask why.
The honest framing is this: correcting drainage manages the load on the soil supporting your foundation. It removes a cause. It does not undo history, and we will not pretend otherwise to sell a trench.
Perimeter clay loses moisture faster than protected interior soil.
Uneven moisture, not total moisture, is what moves a slab.
Erosion · Guide 04
Erosion rarely announces itself. There is no single morning when a slope fails. It moves a small amount with every storm, and because the change between two consecutive weeks is invisible, most people do not register it until something structural is involved — a fence post hanging in air, an exposed irrigation line, a patio slab with a void beneath one corner.
These are the signs that are visible long before that, and every one of them is something you can check on a Saturday walk.
Look at the low end of your property after a storm. A fan of silt on a sidewalk, a line of grit across a driveway apron, a layer of fine soil in the street gutter, mud on the lowest inch of a fence board. Soil that appears somewhere flat has left somewhere sloped. Follow the trail uphill and you will find the source.
Tree roots that were covered two years ago and are now bare have not grown upward; the soil around them has left. The same applies to the crown of a shrub sitting proud of the bed, sprinkler heads that seem to be getting taller, and the top of a valve box or clean out that now stands above grade. Fixed objects are your reference marks. When they appear to rise, the ground fell.
After a hard rain, look for narrow parallel channels an inch wide running down a slope. Those are rills, and they are the first stage. Left alone they merge and deepen into gullies that concentrate flow, which accelerates the process. Rills are cheap to address. Gullies mean rebuilding the slope.
Where turf meets concrete — a walkway, patio, pool deck, driveway — check for a gap or a lip where the soil has dropped below the edge of the slab. Probe it. A void under a slab edge is water taking soil away from underneath, and it will eventually crack that slab. The same check applies at retaining walls: soil pulling away from the back of a wall, or a bulge or lean in the wall face, means water is moving behind it and the drainage behind that wall is not working.
Homeowners usually treat these as a turf problem and reseed. If a patch on a slope refuses to establish year after year, the seed and topsoil are washing off before roots can hold. That is erosion presenting as a lawn complaint. Stabilize the surface first and the planting will succeed on the next attempt.
Properties backing to a creek or drainage easement in Flower Mound, Roanoke or along the Trophy Club corridor have a specific pattern to watch: a vertical, freshly cut face on the bank, trees leaning toward the water, and a shelf of soil at the base. That is active bank retreat, and the distance between that bank and anything you care about is the number that matters. Measure it from a fixed point — a fence corner, not a tree — and write the date down. If the number changes in a year, act.
Erosion is driven by velocity and volume of concentrated flow, not by rainfall alone. A slope that has handled twenty years of storms can start failing after a neighbor regrades uphill, after a new roof valley redirects half a roof onto one downspout, or after a cracked irrigation lateral introduces water into a slope every third morning. When we assess erosion, the first thing we look for is what changed upstream, because treating the scar without removing the cause buys one season.
Fencing · Guide 05
A leaning fence is almost never a board problem, a picket problem or a wind problem. It is a post problem, and post problems are soil problems. In expansive clay, the fence is the most exposed structure on a property: tall, flat, catching wind like a sail, held up by nothing but a column of concrete in soil that changes volume with the seasons.
The active zone — the depth of soil that shrinks and swells with weather — extends well below the surface in North Texas clay. A post set only a foot or two deep sits entirely inside that moving layer. Every wet-dry cycle works it a little looser, and once the concrete plug has a gap around it, water enters and the cycle speeds up. As typical practice for an eight-foot privacy fence here, posts want to be set on the order of two and a half to three feet deep, with the hole bell-shaped or at least wider at the bottom, and the concrete crowned above grade so water runs off rather than pooling at the post. Deeper is not a slogan; it is the difference between a post anchored below the active zone and one floating in it.
Two failures we see constantly. First, a concrete collar finished flat or dished, which turns every post into a small cistern that holds water against the wood. Second, a post set in dirt with a bag of dry mix poured around it and never properly wetted or vibrated, leaving voids. Both produce rot at the exact point of maximum leverage: right at grade. When a wood post fails, it fails there, not at the bottom.
A solid eight-foot privacy fence presents a continuous surface to gusts. That load transfers into the posts as bending moment, highest at grade. Spacing posts too far apart, using undersized posts, or attaching only two rails instead of three multiplies the load each post carries. A fence that leans uniformly along one run in the direction of the prevailing wind is telling you the posts were spaced or sized for a shorter fence.
Fence lines frequently run along the lowest part of a lot, or along a drainage swale between properties. Posts sitting in soil that stays saturated after every storm are in the worst possible condition: wood in constant moisture, clay at maximum swell, and often soil washing away from the base at the same time. If one section of an otherwise sound fence leans, walk that section during a rain. You will usually find water running along it.
Gates are the early warning system. They are the heaviest, most leveraged part of the fence, and a gate that has begun to drag, that needs lifting to latch, or whose gap has gone from parallel to wedge-shaped is announcing that its hinge post has moved. Fix it at that stage and you are resetting one post. Ignore it and the post takes the adjacent panels with it.
Depth, hole diameter, concrete detail, post spacing, three rails instead of two, hardware rated for the gate weight, and a bottom board held clear of the soil so it is not wicking moisture. None of that is visible from the street, which is precisely why it is the first thing cut from a cheap bid. A fence built correctly in clay looks identical to one that is not — for about two years.
At grade, under bending load, in soil that changes volume. Depth and concrete detail are the whole argument.
Seasonal · Guide 06
Most irrigation controllers ship with a default program written for nowhere in particular: a fixed number of minutes, every other day, all year. In this region that program is wrong eleven months out of twelve. Our climate does not do averages. April can deliver several inches in a week; August can deliver nothing for a month while the air pulls moisture out of soil and plants at maximum rate.
A better rhythm follows three rules that matter far more than the exact minute count.
Warm-season turf here — bermuda, zoysia, St. Augustine — roots to whatever depth you consistently wet. Short daily cycles train roots to live in the top inch, which is the first inch to dry out in July. Fewer, longer soakings push roots deeper and make the lawn far more tolerant of heat and of the two-day-a-week schedules most cities here use during summer.
Spray heads apply water much faster than clay can take it. Run a spray zone twenty minutes straight on any slope and most of the last ten minutes leaves the property. The fix is to split the run: two or three shorter cycles with a gap between them, so applied water has time to move down before more arrives. Every modern controller can do this. It is the single highest-value setting change on a North Texas system.
Minutes are meaningless without knowing your application rate. A spray zone might apply well over an inch per hour; a rotor zone often applies a third of that; drip is different again. Put out catch cups, run fifteen minutes, measure, and you will know how many minutes your system needs to deliver a given depth. Then, and only then, do run times become real numbers rather than guesses.
With those three rules in place, the calendar below is a starting frame. It is guidance for a typical established warm-season lawn on clay in this region, not a rule and not a schedule to copy blindly. Rain, soil, sun exposure, slope and your city’s current watering ordinance all override it.
| Month | What the lawn is doing | Typical target, water per week | Watch for |
|---|---|---|---|
| January | Fully dormant | System off | Soil moisture near the foundation during long dry spells |
| February | Dormant, freeze risk | System off | Backflow assembly insulated; split pipe after a hard freeze |
| March | Green-up begins | Roughly 0.5–0.75 in | Spring start-up: run every zone once and watch it |
| April | Active growth, often our wettest stretch | Often nothing needed | Rain sensor working; do not water through a wet week |
| May | Peak growth | Roughly 1 in | Coverage gaps become visible as growth accelerates |
| June | Heat sets in | Roughly 1–1.25 in | Shift all cycles to early morning; wind drift by afternoon |
| July | Heat stress, maximum demand | Roughly 1.25–1.75 in | Cycle and soak; city restrictions; hot spots along drives and walks |
| August | Peak stress, driest stretch | Roughly 1.25–1.75 in | Perimeter soil drying and pulling away from the slab |
| September | Heat eases late in the month | Roughly 1 in | Reduce run times rather than skipping whole zones |
| October | Growth slowing | Roughly 0.5–0.75 in | Basins and grates cleared before the first heavy fall rain |
| November | Entering dormancy | Occasional deep soak only | Schedule winterization; keep soil from going bone dry |
| December | Dormant | System off | Freeze protection at the backflow, valves and exposed piping |
Water between roughly 4 a.m. and shortly after sunrise. Wind is lowest, evaporation is lowest, and the blades dry before disease pressure builds. Evening watering leaves turf wet all night, which is how fungus gets invited in.
And walk the lawn once a week while a zone runs. A rain sensor that has failed, a nozzle that has clogged, a head that a mower clipped — all of it is obvious while the system is running and invisible when it is not. A controller cannot see your yard. You can.
Systems · Guide 07
These three get sold as separate trades, which is why properties end up with three contractors solving three symptoms of one condition. In reality they are a single water system with three roles: grading decides where water goes, drainage decides how fast it leaves, irrigation decides how much you add. Change one and you have changed the other two whether you intended to or not.
Everything else operates inside the shape of the ground. Slope direction and steepness determine which areas shed and which collect, which areas dry out first, and where runoff concentrates. An irrigation design that ignores grade will overwater the bottom of a slope while starving the top, because gravity redistributes what the heads apply. Zoning by elevation and exposure — not by convenience of pipe routing — is what makes a hillside lawn uniform.
Every property has a capacity: the volume of water it can accept and move away without standing. If drainage capacity is exceeded, additional water has nowhere to go, and that includes irrigation water. We have diagnosed “drainage” problems that turned out to be an irrigation schedule adding a half inch every morning to a low area that had not dried out since the last storm. We have also seen new drainage systems fail because a leaking mainline kept feeding them water no rain event explained.
You cannot schedule rainfall, but the irrigation controller runs on your terms. That makes it the fastest lever and the most common hidden cause. A single stuck valve can put hundreds of gallons a day into one part of a yard. A misaligned head watering a fence line soaks the exact soil holding your fence posts. Drip left running in a bed against the house maintains a permanent wet band along one elevation of the foundation. In each case the visible failure is somewhere other than the irrigation system.
Order of operations decides cost. Correct grade first, then drainage, then irrigation, then surface. Doing it backwards means paying twice: new sod torn up for a drain line, a fresh irrigation layout abandoned after a regrade, a stabilized slope reopened because the pipe underneath was never installed. When one team holds all four, sequence is a plan. When four contractors hold one each, sequence is a negotiation, and you are the one holding it together.
This is the whole reason Sunday is structured the way it is. Not to sell more scope — often the systems view reduces scope, because the real fix turns out to be one valve and two downspouts rather than the trenching project someone quoted.
Solve any one in isolation and you have usually moved the problem, not removed it.
Ownership · Guide 08
“Free estimate” covers an enormous range of behavior. At one end, someone stands in your driveway, looks at a brown patch, and writes a number on a pad. At the other, someone runs your system zone by zone, shoots elevations, opens valve boxes and hands you a written condition report. Both are free. Only one of them tells you anything.
Use this as a checklist. It applies to us and to anyone else you invite onto the property.
Every zone runs while someone watches it. Nobody can evaluate an irrigation system that is switched off, and no photograph substitutes. Expect notes per zone: head type, coverage, pressure behavior, obvious losses.
Standing water gets traced to its source and to its intended exit. That means looking at downspout locations, at the grade between the house and the low point, at where the property line falls, and at whether a legal discharge point exists. An assessment that stops at “you need a French drain here” skipped the part that determines whether the drain will work.
Eyes are unreliable on slopes under 2%. If a recommendation depends on fall — and most drainage recommendations do — someone should be shooting grade with a level or laser, not squinting.
Valve boxes, backflow assembly, controller enclosure, catch basins. Standing water in a valve box, corroded splices, a bypassed rain sensor, a backflow device that has never been tested — these are found by lifting lids, which takes five minutes and is skipped constantly.
You called about a dry patch. The fence line, the slope behind the pool, the bed against the brick and the gate that drags are all part of the same property, and all of them are cheaper to address early. Noting them is not upselling; recommending immediate work on all of them is. A good report separates now, next season and watch it.
A real scope says how many heads, how many linear feet of pipe at what diameter and depth, how many basins, how many cubic yards of soil, what is being restored, and explicitly what is not included. A single lump sum with a one-line description is not a scope; it is a hope. Exclusions matter as much as inclusions — sod restoration, permit fees, rock excavation, tree root conflicts, sprinkler repairs discovered during trenching.
The most useful sentence in any assessment is a version of “you do not need that yet.” If every visit produces a recommendation to buy everything at once, the assessment is a sales call with a clipboard.
Seasonal checklist
None of this requires a technician. All of it catches problems while they are still inexpensive.
Next step
Some of what is on this page you can act on yourself this weekend. The rest needs someone standing in the yard with the system running. That part is what we do.
Seasonal service
Each fall Sunday adds lighting to the work we already do on your property — permanent architectural systems that stay on the roofline year-round, and seasonal holiday installs we hang, service and take down for you.
All lighting installations booked before November 1. Design and quote at no charge.
Discount applies to new lighting installations scheduled between September and January. Ask us about bundling with a maintenance plan.